From 93aa2e472a04a7050320136faf19a511f4e4324f Mon Sep 17 00:00:00 2001
From: Gareth Evans <gareth.evans@contextis.co.uk>
Date: Wed, 1 Feb 2017 23:44:00 +0000
Subject: [PATCH 1/6] Add genericised image handling and implement in DoRxdPwr

---
 Makefile     |   8 ++-
 image-ppm.cc |  61 ++++++++++++++++
 image-ppm.hh |  13 ++++
 image.cc     | 199 +++++++++++++++++++++++++++++++++++++++++++++++++++
 image.hh     |  42 +++++++++++
 main.cc      |   9 +++
 outputs.cc   |  62 +++++++---------
 7 files changed, 357 insertions(+), 37 deletions(-)
 create mode 100644 image-ppm.cc
 create mode 100644 image-ppm.hh
 create mode 100644 image.cc
 create mode 100644 image.hh

diff --git a/Makefile b/Makefile
index a82615a..65d44ff 100644
--- a/Makefile
+++ b/Makefile
@@ -4,11 +4,11 @@ CC		= gcc
 CXX		= g++
 CFLAGS		= -Wall -O3 -s -ffast-math
 CXXFLAGS	= -Wall -O3 -s -ffast-math
-LIBS		= -lm -lpthread
+LIBS		= -lm -lpthread -ldl
 
 VPATH		= models
 objects 	= main.o cost.o ecc33.o ericsson.o fspl.o hata.o itwom3.0.o \
-		  los.o sui.o pel.o inputs.o outputs.o
+		  los.o sui.o pel.o inputs.o outputs.o image.o image-ppm.o
 
 GCC_MAJOR	:= $(shell $(CXX) -dumpversion 2>&1 | cut -d . -f 1)
 GCC_MINOR	:= $(shell $(CXX) -dumpversion 2>&1 | cut -d . -f 2)
@@ -45,6 +45,10 @@ inputs.o: inputs.cc common.h main.hh
 outputs.o: outputs.cc common.h inputs.hh main.hh cost.hh ecc33.hh ericsson.hh \
 	   fspl.hh hata.hh itwom3.0.hh sui.hh pel.hh
 
+image.o: image.cc image-ppm.o
+
+image-ppm.o: image-ppm.cc
+
 los.o: los.cc common.h main.hh cost.hh ecc33.hh ericsson.hh fspl.hh hata.hh \
        itwom3.0.hh sui.hh pel.hh
 
diff --git a/image-ppm.cc b/image-ppm.cc
new file mode 100644
index 0000000..f37bbe2
--- /dev/null
+++ b/image-ppm.cc
@@ -0,0 +1,61 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <errno.h>
+#include "image.hh"
+
+int ppm_init(PIMAGE_CTX ctx){
+	size_t buf_size;
+
+	/* Perform simple sanity checking */
+	if(ctx->canvas != NULL)
+		return EINVAL;
+	ctx->model = IMAGE_RGB; //Override this as we only support RGB
+	ctx->format = IMAGE_PPM;
+	ctx->extension = ".ppm";
+
+	buf_size = ctx->width * ctx->height * RGB_SIZE;
+
+	ctx->canvas = (uint8_t*) calloc(buf_size,sizeof(uint8_t));
+	ctx->next_pixel = ctx->canvas;
+	if(ctx->canvas == NULL)
+		return ENOMEM;
+
+	return 0;
+}
+
+int ppm_add_pixel(PIMAGE_CTX ctx,const uint8_t r,const uint8_t g,const uint8_t b,const uint8_t a){
+	register uint8_t* next;
+
+	next = ctx->next_pixel;
+
+	next[0] = r;
+	next[1] = g;
+	next[2] = b;
+	/*if(ctx->model == IMAGE_RGBA){
+		next[3] = a;
+		ctx->next_pixel += 1;
+	}*/
+	ctx->next_pixel += 3;
+
+	return 0;
+}
+
+int ppm_get_pixel(PIMAGE_CTX ctx,const size_t x,const size_t y,const uint8_t *r,const uint8_t *g,const uint8_t *b,const uint8_t *a){
+	/* STUB */
+	return 0;
+}
+
+int ppm_write(PIMAGE_CTX ctx, FILE* fd){
+	size_t written;
+	size_t count;
+
+	count = ctx->width * ctx->height * RGB_SIZE;
+
+	fprintf(fd, "P6\n%zu %zu\n255\n", ctx->width, ctx->height);
+	written = fwrite(ctx->canvas,sizeof(uint8_t),count,fd);
+	if(written < count)
+		return EPIPE;
+	
+	return 0;
+}
\ No newline at end of file
diff --git a/image-ppm.hh b/image-ppm.hh
new file mode 100644
index 0000000..4831f0a
--- /dev/null
+++ b/image-ppm.hh
@@ -0,0 +1,13 @@
+#ifndef _IMAGE_PPM_HH
+#define _IMAGE_PPM_HH
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+
+int ppm_init(PIMAGE_CTX ctx);
+int ppm_add_pixel(PIMAGE_CTX ctx,const uint8_t r,const uint8_t g,const uint8_t b,const uint8_t a);
+int ppm_get_pixel(PIMAGE_CTX ctx,const size_t x,const size_t y,const uint8_t *r,const uint8_t *g,const uint8_t *b,const uint8_t *a);
+int ppm_write(PIMAGE_CTX ctx, FILE* fd);
+
+#endif
\ No newline at end of file
diff --git a/image.cc b/image.cc
new file mode 100644
index 0000000..467e655
--- /dev/null
+++ b/image.cc
@@ -0,0 +1,199 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <errno.h>
+#include <dlfcn.h>
+#include "image.hh"
+#include "image-ppm.hh"
+
+typedef int _init(PIMAGE_CTX);
+typedef int _add_pixel(PIMAGE_CTX,const uint8_t,const uint8_t,const uint8_t,const uint8_t);
+typedef int _get_pixel(PIMAGE_CTX,const size_t,const size_t,const uint8_t*,const uint8_t*,const uint8_t*,const uint8_t*);
+typedef int _write(PIMAGE_CTX,FILE*);
+
+struct image_dispatch_table{
+	_init *init;
+	_add_pixel *add_pixel;
+	_get_pixel *get_pixel;
+	_write *write;
+};
+
+static IMAGE_FORMAT format = IMAGE_PPM;
+char *dynamic_backend = NULL;
+
+int load_library(struct image_dispatch_table *dt){
+	void *hndl;
+	int success = 0;
+
+	if(dynamic_backend == NULL){
+		fprintf(stderr,"Custom image processor requested without specification\n");
+		return EINVAL;
+	}
+	
+	hndl = dlopen(dynamic_backend,RTLD_LAZY);
+	if(hndl == NULL){
+		fprintf(stderr,"Error loading shared object\n");
+		return EINVAL;
+	}
+	
+	dt->init = (_init*)dlsym(hndl,"lib_init");
+	dt->add_pixel = (_add_pixel*)dlsym(hndl,"lib_add_pixel");
+	dt->get_pixel = (_get_pixel*)dlsym(hndl,"lib_get_pixel");
+	dt->write = (_write*)dlsym(hndl,"lib_write");
+
+	if(dt->init == NULL ||
+		dt->add_pixel == NULL ||
+		dt->get_pixel == NULL ||
+		dt->write == NULL){
+		fprintf(stderr,"Invalid image processing module specified\n");
+		success = dlclose(hndl);
+	}
+
+	return success;
+}
+
+int get_dt(struct image_dispatch_table *dt, IMAGE_FORMAT format){
+	int success = 0;
+
+	memset((void*)dt,0x00,sizeof(struct image_dispatch_table));
+	switch(format){
+		case IMAGE_PPM:
+			dt->init = ppm_init;
+			dt->add_pixel = ppm_add_pixel;
+			dt->get_pixel = ppm_get_pixel;
+			dt->write = ppm_write;
+			break;
+		case IMAGE_LIBRARY:
+			success = load_library(dt);
+			break;
+		default:
+			success = EINVAL;
+	}
+	return success;
+}
+
+int image_init(PIMAGE_CTX ctx, \
+				const size_t width, \
+				const size_t height, \
+				const IMAGE_MODEL model) {
+
+	int success = 0;
+	struct image_dispatch_table *dt;
+
+	/* Perform some sanity checking on provided arguments */
+	if(ctx == NULL)
+		return EINVAL;
+	if(width == 0 || height == 0)
+		return EINVAL;
+	if(model < 0 || model > IMAGE_MODEL_MAX)
+		return EINVAL;
+	if(format < 0 || format > IMAGE_FORMAT_MAX)
+		return EINVAL;
+
+	memset(ctx,0x00,sizeof(IMAGE_CTX));
+
+	/* Assign the initialize values to the processing context */
+	ctx->width = width;
+	ctx->height = height;
+	ctx->model = model;
+	ctx->format = format;
+
+	/* Get the dispatch table for this image format */
+	dt = (struct image_dispatch_table*) calloc(1,sizeof(struct image_dispatch_table));
+	if(dt == NULL){
+		fprintf(stderr,"Error allocating dispatch table\n");
+		return ENOMEM;
+	}
+	success = get_dt(dt,format);
+	if(success != 0){
+		fprintf(stderr,"Error locating dispatch table\n");
+		free(dt);
+		return success;
+	}
+	ctx->_dt = (void*)dt;
+
+	/* Call the format-specific initialization function */
+	success = dt->init(ctx);
+	if(success != 0){
+		fprintf(stderr,"Error initializing image context\n");
+		free(dt);
+		return success;
+	}
+
+	ctx->initialized = 1;
+
+	return success;
+}
+int image_add_pixel(PIMAGE_CTX ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
+	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	return dt->add_pixel(ctx,r,g,b,a);
+}
+int image_set_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
+	size_t block_size;
+	block_size = ctx->model == IMAGE_RGB ? RGB_SIZE : RGBA_SIZE;
+	ctx->next_pixel = ctx->canvas + (x * block_size) + (ctx->width * block_size * y);
+	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	return dt->add_pixel(ctx,r,g,b,a);
+}
+int image_get_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t *r, const uint8_t *g, const uint8_t *b, const uint8_t *a){
+	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	return dt->get_pixel(ctx,x,y,r,g,b,a);
+}
+int image_get_filename(PIMAGE_CTX ctx, char *out, size_t len_out, char *in){
+	size_t len_src;
+	size_t len_ext;
+	int success = 0;
+
+	if(ctx->initialized != 1){
+		fprintf(stderr,"Called get filename before initialization\n");
+		return EINVAL;
+	}
+
+	len_src = strlen(in);
+	len_ext = strlen(ctx->extension);
+
+	if(len_src == 0){
+		in = "output";
+		len_src = 6;
+	}
+
+	if(len_src > len_ext && strcmp(in+len_src-len_ext,ctx->extension) == 0){
+		/* Already has correct extension and fits in buffer */
+		if(len_src < len_out)
+			strncpy(in,out,len_out);
+		else
+			success = ENOMEM;
+	}else if(len_src > len_ext){
+		/* Doesn't have correct extension and fits */
+		if(len_src + len_ext < len_out){
+			strncpy(out,in,len_out);
+			strncat(out,ctx->extension,len_out);
+		}else
+			success = ENOMEM;
+	}else{
+		/* The input buffer plus an extension cannot fit in the output buffer */
+		fprintf(stderr,"Error building image output filename\n");
+		success = ENOMEM;
+	}
+	return success;
+}
+int image_write(PIMAGE_CTX ctx, FILE *fd){
+	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	return dt->write(ctx,fd);
+}
+int image_set_library(char *library){
+	char *libname;
+	size_t length;
+
+	length = strlen(library) + 1;
+	libname = (char*)calloc(length,sizeof(char));
+	if(libname == NULL)
+		return ENOMEM;
+	strncpy(libname,library,length);
+
+	dynamic_backend = libname;
+	format = IMAGE_LIBRARY;
+	return 0;
+}
+
diff --git a/image.hh b/image.hh
new file mode 100644
index 0000000..f620508
--- /dev/null
+++ b/image.hh
@@ -0,0 +1,42 @@
+#ifndef _IMAGE_HH_
+#define _IMAGE_HH_
+
+#include <stdint.h>
+
+#define RGB_SIZE  3
+#define RGBA_SIZE 4
+
+typedef enum _IMAGE_FORMAT{	IMAGE_PPM, \
+							IMAGE_LIBRARY, \
+							IMAGE_FORMAT_MAX \
+						} IMAGE_FORMAT;
+
+typedef enum _IMAGE_MODEL{	IMAGE_RGB, \
+							IMAGE_RGBA, \
+							IMAGE_MODEL_MAX
+						} IMAGE_MODEL;
+
+typedef struct _IMAGE_CTX{
+	size_t width;
+	size_t height;
+	IMAGE_MODEL model;
+	IMAGE_FORMAT format;
+	uint8_t *canvas;
+	uint8_t *next_pixel;
+	uint32_t initialized;
+	char *extension;
+	void *_dt;
+} IMAGE_CTX, *PIMAGE_CTX;
+
+int image_init(PIMAGE_CTX ctx, const size_t width, const size_t height, const IMAGE_MODEL model);
+int image_add_pixel(PIMAGE_CTX ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a);
+int image_set_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a);
+int image_get_pixel(PIMAGE_CTX ctx,const size_t x,const size_t y, uint8_t const *r, uint8_t const *g, uint8_t const *b, uint8_t const *a);
+int image_get_filename(PIMAGE_CTX ctx, char* out, size_t len, char* in);
+int image_write(PIMAGE_CTX ctx, FILE *fd);
+int image_set_library(char *library);
+
+#define ADD_PIXEL(ctx,r,g,b) image_add_pixel((ctx),(r),(g),(b),0)
+#define ADD_PIXELA(ctx,r,g,b,a) image_add_pixel((ctx),(r),(g),(b),(a))
+
+#endif
\ No newline at end of file
diff --git a/main.cc b/main.cc
index d5c2902..c4f5ea3 100644
--- a/main.cc
+++ b/main.cc
@@ -35,6 +35,7 @@ double version = 2.95;
 #include "models/itwom3.0.hh"
 #include "models/los.hh"
 #include "models/pel.hh"
+#include "image.hh"
 
 int MAXPAGES = 64;
 int ARRAYSIZE = 76810;//76810;
@@ -1210,6 +1211,14 @@ int main(int argc, char *argv[])
 			}
 		}
 
+		if (strcmp(argv[x], "-so") == 0) {
+			z = x + 1;
+			if(image_set_library(argv[z]) != 0){
+				fprintf(stderr,"Error configuring image processor\n");
+				exit(EINVAL);
+			}
+		}
+
 		if (strcmp(argv[x], "-rt") == 0) {
 			z = x + 1;
 
diff --git a/outputs.cc b/outputs.cc
index 77b4a8c..ca90da5 100644
--- a/outputs.cc
+++ b/outputs.cc
@@ -14,6 +14,7 @@
 #include "models/hata.hh"
 #include "models/itwom3.0.hh"
 #include "models/sui.hh"
+#include "image.hh"
 
 void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 		unsigned char ngs, struct site *xmtr, unsigned char txsites)
@@ -529,6 +530,13 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, z = 1, x0 = 0, y0 = 0, dBm, match;
 	double conversion, one_over_gamma, lat, lon, minwest;
 	FILE *fd;
+	IMAGE_CTX ctx;
+	int success;
+
+	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB)) != 0){
+		fprintf(stderr,"Error initializing image\n");
+		exit(success);
+	}
 
 	one_over_gamma = 1.0 / GAMMA;
 	conversion =
@@ -544,24 +552,11 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 			filename[strlen(filename) - 4] = 0;	/* Remove .qth */
 		}
 
-		y = strlen(filename);
-
-		if (y > 4) {
-			if (filename[y - 1] == 'm' && filename[y - 2] == 'p'
-			    && filename[y - 3] == 'p' && filename[y - 4] == '.')
-				y -= 4;
+		if(image_get_filename(&ctx,mapfile,sizeof(mapfile),filename) != 0){
+			fprintf(stderr,"Error creating file name\n");
+			exit(1);
 		}
 
-		for (x = 0; x < y; x++) {
-			mapfile[x] = filename[x];
-		}
-
-		mapfile[x] = '.';
-		mapfile[x + 1] = 'p';
-		mapfile[x + 2] = 'p';
-		mapfile[x + 3] = 'm';
-		mapfile[x + 4] = 0;
-
 		fd = fopen(mapfile,"wb");
 
 	} else {
@@ -583,7 +578,6 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 	east = (minwest < 180.0 ? -minwest : 360.0 - min_west);
 	west = (double)(max_west < 180 ? -max_west : 360 - max_west);
 
-	fprintf(fd, "P6\n%u %u\n255\n", width, (kml ? height : height));
 	if (debug) {
 		fprintf(stderr, "\nWriting \"%s\" (%ux%u pixmap image)...\n",
 			(filename != NULL ? mapfile : "to stdout"), width, (kml ? height : height));
@@ -652,11 +646,11 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 
 					if (red >= 180 && green <= 75
 					    && blue <= 75 && dBm != 0)
-						fprintf(fd, "%c%c%c", 255 ^ red,
+						ADD_PIXEL(&ctx, 255 ^ red,
 							255 ^ green,
 							255 ^ blue);
 					else
-						fprintf(fd, "%c%c%c", 255, 0,
+						ADD_PIXEL(&ctx, 255, 0,
 							0);
 
 					cityorcounty = 1;
@@ -664,7 +658,7 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 
 				else if (mask & 4) {
 					/* County Boundaries: Black */
-					fprintf(fd, "%c%c%c", 0, 0, 0);
+					ADD_PIXEL(&ctx, 0, 0, 0);
 					cityorcounty = 1;
 				}
 
@@ -672,15 +666,14 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 					if (contour_threshold != 0
 					    && dBm < contour_threshold) {
 						if (ngs)	/* No terrain */
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx,
 								255, 255, 255);
 						else {
 							/* Display land or sea elevation */
 
 							if (dem[indx].
 							    data[x0][y0] == 0)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx,
 									0, 0,
 									170);
 							else {
@@ -688,8 +681,7 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 								    (unsigned)
 								    (0.5 +
 								     pow((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx,
 									terrain,
 									terrain,
 									terrain);
@@ -702,15 +694,14 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 
 						if (red != 0 || green != 0
 						    || blue != 0)
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx,
 								red, green,
 								blue);
 
 						else {	/* terrain / sea-level */
 
 							if (ngs)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									255,
 									255,
 									255); // WHITE
@@ -718,9 +709,7 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 								if (dem[indx].
 								    data[x0][y0]
 								    == 0)
-									fprintf
-									    (fd,
-									     "%c%c%c",
+									ADD_PIXEL(&ctx, 
 									     0,
 									     0,
 									     170); // BLUE
@@ -733,9 +722,7 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 									     +
 									     pow
 									     ((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-									fprintf
-									    (fd,
-									     "%c%c%c",
+									ADD_PIXEL(&ctx, 
 									     terrain,
 									     terrain,
 									     terrain);
@@ -750,11 +737,16 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 				/* We should never get here, but if */
 				/* we do, display the region as black */
 
-				fprintf(fd, "%c%c%c", 0, 0, 0);
+				ADD_PIXEL(&ctx, 0, 0, 0);
 			}
 		}
 	}
 
+	if((success = image_write(&ctx,fd)) != 0){
+		fprintf(stderr,"Error writing image\n");
+		exit(success);
+	}
+
 	fflush(fd);
 
 	if( filename != NULL ) {

From fb950bafef3032c55e8b1a2da9124af7319dfdb7 Mon Sep 17 00:00:00 2001
From: Gareth Evans <gareth.evans@contextis.co.uk>
Date: Thu, 2 Feb 2017 12:35:19 +0000
Subject: [PATCH 2/6] Large code cleanup of image rendering engine

---
 image-ppm.cc |   6 +-
 image.cc     | 196 +++++++++++++++++++++++++++++++++++----------------
 image.hh     |  20 +++---
 outputs.cc   |   2 +-
 4 files changed, 149 insertions(+), 75 deletions(-)

diff --git a/image-ppm.cc b/image-ppm.cc
index f37bbe2..a9d8044 100644
--- a/image-ppm.cc
+++ b/image-ppm.cc
@@ -16,6 +16,7 @@ int ppm_init(PIMAGE_CTX ctx){
 
 	buf_size = ctx->width * ctx->height * RGB_SIZE;
 
+	/* Allocate the canvas buffer */
 	ctx->canvas = (uint8_t*) calloc(buf_size,sizeof(uint8_t));
 	ctx->next_pixel = ctx->canvas;
 	if(ctx->canvas == NULL)
@@ -32,10 +33,7 @@ int ppm_add_pixel(PIMAGE_CTX ctx,const uint8_t r,const uint8_t g,const uint8_t b
 	next[0] = r;
 	next[1] = g;
 	next[2] = b;
-	/*if(ctx->model == IMAGE_RGBA){
-		next[3] = a;
-		ctx->next_pixel += 1;
-	}*/
+
 	ctx->next_pixel += 3;
 
 	return 0;
diff --git a/image.cc b/image.cc
index 467e655..da67bef 100644
--- a/image.cc
+++ b/image.cc
@@ -1,3 +1,10 @@
+/*
+ * Generic image output handling. This feature allows
+ * for extensible image output formats and permits for
+ * cleaner image rendering code in the model generation
+ * routines by moving all of the file-format specific
+ * logic to be handled here.
+ */
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
@@ -12,6 +19,9 @@ typedef int _add_pixel(PIMAGE_CTX,const uint8_t,const uint8_t,const uint8_t,cons
 typedef int _get_pixel(PIMAGE_CTX,const size_t,const size_t,const uint8_t*,const uint8_t*,const uint8_t*,const uint8_t*);
 typedef int _write(PIMAGE_CTX,FILE*);
 
+int get_dt(struct image_dispatch_table *dt, IMAGE_FORMAT format);
+int load_library(struct image_dispatch_table *dt);
+
 struct image_dispatch_table{
 	_init *init;
 	_add_pixel *add_pixel;
@@ -19,64 +29,31 @@ struct image_dispatch_table{
 	_write *write;
 };
 
-static IMAGE_FORMAT format = IMAGE_PPM;
+static IMAGE_FORMAT default_format = IMAGE_PPM;
 char *dynamic_backend = NULL;
 
-int load_library(struct image_dispatch_table *dt){
-	void *hndl;
-	int success = 0;
-
-	if(dynamic_backend == NULL){
-		fprintf(stderr,"Custom image processor requested without specification\n");
+/*
+ * image_set_format
+ * Changes the default format for the next
+ * uninitialized image canvas
+ */
+int image_set_format(IMAGE_FORMAT format){
+	if(format <= IMAGE_DEFAULT || format >= IMAGE_FORMAT_MAX)
 		return EINVAL;
-	}
-	
-	hndl = dlopen(dynamic_backend,RTLD_LAZY);
-	if(hndl == NULL){
-		fprintf(stderr,"Error loading shared object\n");
-		return EINVAL;
-	}
-	
-	dt->init = (_init*)dlsym(hndl,"lib_init");
-	dt->add_pixel = (_add_pixel*)dlsym(hndl,"lib_add_pixel");
-	dt->get_pixel = (_get_pixel*)dlsym(hndl,"lib_get_pixel");
-	dt->write = (_write*)dlsym(hndl,"lib_write");
-
-	if(dt->init == NULL ||
-		dt->add_pixel == NULL ||
-		dt->get_pixel == NULL ||
-		dt->write == NULL){
-		fprintf(stderr,"Invalid image processing module specified\n");
-		success = dlclose(hndl);
-	}
-
-	return success;
-}
-
-int get_dt(struct image_dispatch_table *dt, IMAGE_FORMAT format){
-	int success = 0;
-
-	memset((void*)dt,0x00,sizeof(struct image_dispatch_table));
-	switch(format){
-		case IMAGE_PPM:
-			dt->init = ppm_init;
-			dt->add_pixel = ppm_add_pixel;
-			dt->get_pixel = ppm_get_pixel;
-			dt->write = ppm_write;
-			break;
-		case IMAGE_LIBRARY:
-			success = load_library(dt);
-			break;
-		default:
-			success = EINVAL;
-	}
-	return success;
+	default_format = format;
+	return 0;
 }
 
+/*
+ * image_init
+ * Initialize an image context. Must be called
+ * before attempting to write any image data
+ */
 int image_init(PIMAGE_CTX ctx, \
 				const size_t width, \
 				const size_t height, \
-				const IMAGE_MODEL model) {
+				const IMAGE_MODEL model, \
+				const IMAGE_FORMAT format) {
 
 	int success = 0;
 	struct image_dispatch_table *dt;
@@ -88,7 +65,7 @@ int image_init(PIMAGE_CTX ctx, \
 		return EINVAL;
 	if(model < 0 || model > IMAGE_MODEL_MAX)
 		return EINVAL;
-	if(format < 0 || format > IMAGE_FORMAT_MAX)
+	if(format >= IMAGE_FORMAT_MAX || (format == IMAGE_LIBRARY && dynamic_backend == NULL))
 		return EINVAL;
 
 	memset(ctx,0x00,sizeof(IMAGE_CTX));
@@ -97,7 +74,10 @@ int image_init(PIMAGE_CTX ctx, \
 	ctx->width = width;
 	ctx->height = height;
 	ctx->model = model;
-	ctx->format = format;
+	if(format == IMAGE_DEFAULT)
+		ctx->format = default_format;
+	else
+		ctx->format = format;
 
 	/* Get the dispatch table for this image format */
 	dt = (struct image_dispatch_table*) calloc(1,sizeof(struct image_dispatch_table));
@@ -105,7 +85,7 @@ int image_init(PIMAGE_CTX ctx, \
 		fprintf(stderr,"Error allocating dispatch table\n");
 		return ENOMEM;
 	}
-	success = get_dt(dt,format);
+	success = get_dt(dt,ctx->format);
 	if(success != 0){
 		fprintf(stderr,"Error locating dispatch table\n");
 		free(dt);
@@ -125,12 +105,20 @@ int image_init(PIMAGE_CTX ctx, \
 
 	return success;
 }
+/*
+ * image_add_pixel, image_set_pixel, image_get_pixel, image_write
+ * Various setters ad getters for assigning pixel data. image_write
+ * takes an open file handle and writes image data to it.
+ * These functions simply wrap the underlying format-specific functions
+ */
 int image_add_pixel(PIMAGE_CTX ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
 	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	if(ctx->initialized != 1) return EINVAL;
 	return dt->add_pixel(ctx,r,g,b,a);
 }
 int image_set_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
 	size_t block_size;
+	if(ctx->initialized != 1) return EINVAL;
 	block_size = ctx->model == IMAGE_RGB ? RGB_SIZE : RGBA_SIZE;
 	ctx->next_pixel = ctx->canvas + (x * block_size) + (ctx->width * block_size * y);
 	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
@@ -138,23 +126,35 @@ int image_set_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_
 }
 int image_get_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t *r, const uint8_t *g, const uint8_t *b, const uint8_t *a){
 	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	if(ctx->initialized != 1) return EINVAL;
 	return dt->get_pixel(ctx,x,y,r,g,b,a);
 }
+int image_write(PIMAGE_CTX ctx, FILE *fd){
+	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+	if(ctx->initialized != 1) return EINVAL;
+	return dt->write(ctx,fd);
+}
+
+/*
+ * image_get_filename
+ * Creates an appropriate file name using data supplied
+ * by the user. If the extension is already correct, return
+ * that; if not append if there is space
+ */
 int image_get_filename(PIMAGE_CTX ctx, char *out, size_t len_out, char *in){
 	size_t len_src;
 	size_t len_ext;
 	int success = 0;
 
-	if(ctx->initialized != 1){
-		fprintf(stderr,"Called get filename before initialization\n");
+	if(ctx->initialized != 1)
 		return EINVAL;
-	}
 
+	/* Get various lengths */
 	len_src = strlen(in);
 	len_ext = strlen(ctx->extension);
 
 	if(len_src == 0){
-		in = "output";
+		in = (char*)"output";
 		len_src = 6;
 	}
 
@@ -178,10 +178,43 @@ int image_get_filename(PIMAGE_CTX ctx, char *out, size_t len_out, char *in){
 	}
 	return success;
 }
-int image_write(PIMAGE_CTX ctx, FILE *fd){
-	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
-	return dt->write(ctx,fd);
+
+/*
+ * get_dt
+ * Load the dispatch table for the specified image
+ * format. Currently only pixmap supported.
+ */
+int get_dt(struct image_dispatch_table *dt, IMAGE_FORMAT format){
+	int success = 0;
+
+	memset((void*)dt,0x00,sizeof(struct image_dispatch_table));
+	switch(format){
+		case IMAGE_PPM:
+			dt->init = ppm_init;
+			dt->add_pixel = ppm_add_pixel;
+			dt->get_pixel = ppm_get_pixel;
+			dt->write = ppm_write;
+			break;
+		case IMAGE_LIBRARY:
+			success = load_library(dt);
+			break;
+		default:
+			success = EINVAL;
+	}
+	return success;
 }
+
+/*
+ * ==WARNING==: Here be dragons!
+ * Experimantal features beyond this point.
+ * Only use if you are sure you know what you
+ * are doing!
+ */
+
+/*
+ * image_set_library
+ * Set the library to use for generating images
+ */
 int image_set_library(char *library){
 	char *libname;
 	size_t length;
@@ -193,7 +226,48 @@ int image_set_library(char *library){
 	strncpy(libname,library,length);
 
 	dynamic_backend = libname;
-	format = IMAGE_LIBRARY;
+	default_format = IMAGE_LIBRARY;
 	return 0;
 }
+/*
+ * image_get_library
+ * Returns the current saved image rendering
+ * library
+ */
+char* image_get_library(){
+	return dynamic_backend;
+}
 
+/* 
+ * load_library
+ * External image processing: experimental feature
+ * Load an external library to perform image processing
+ * It must be a custom compatible library
+ */
+int load_library(struct image_dispatch_table *dt){
+	void *hndl;
+	int success = 0;
+
+	/* Validate object file */
+	if(dynamic_backend == NULL || strlen(dynamic_backend) == 0){
+		fprintf(stderr,"Custom image processor requested without specification\n");
+		return EINVAL;
+	}
+	
+	/* Load shared object and locate required exports */
+	hndl = dlopen(dynamic_backend,RTLD_LAZY);
+	if(hndl == NULL){
+		fprintf(stderr,"Error loading shared object\n");
+		return EINVAL;
+	}
+	/* Perform symbol lookup */
+	if((dt->init = (_init*)dlsym(hndl,"lib_init")) == NULL ||
+		(dt->add_pixel = (_add_pixel*)dlsym(hndl,"lib_add_pixel")) == NULL ||
+		(dt->get_pixel = (_get_pixel*)dlsym(hndl,"lib_get_pixel")) == NULL ||
+		(dt->write = (_write*)dlsym(hndl,"lib_write")) == NULL){
+		fprintf(stderr,"Invalid image processing module specified\n\t%s",dlerror());
+		success = dlclose(hndl);
+	}
+
+	return success;
+}
\ No newline at end of file
diff --git a/image.hh b/image.hh
index f620508..45437d0 100644
--- a/image.hh
+++ b/image.hh
@@ -6,7 +6,8 @@
 #define RGB_SIZE  3
 #define RGBA_SIZE 4
 
-typedef enum _IMAGE_FORMAT{	IMAGE_PPM, \
+typedef enum _IMAGE_FORMAT{	IMAGE_DEFAULT = 0, \
+							IMAGE_PPM, \
 							IMAGE_LIBRARY, \
 							IMAGE_FORMAT_MAX \
 						} IMAGE_FORMAT;
@@ -28,15 +29,16 @@ typedef struct _IMAGE_CTX{
 	void *_dt;
 } IMAGE_CTX, *PIMAGE_CTX;
 
-int image_init(PIMAGE_CTX ctx, const size_t width, const size_t height, const IMAGE_MODEL model);
-int image_add_pixel(PIMAGE_CTX ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a);
-int image_set_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a);
-int image_get_pixel(PIMAGE_CTX ctx,const size_t x,const size_t y, uint8_t const *r, uint8_t const *g, uint8_t const *b, uint8_t const *a);
-int image_get_filename(PIMAGE_CTX ctx, char* out, size_t len, char* in);
-int image_write(PIMAGE_CTX ctx, FILE *fd);
-int image_set_library(char *library);
+int image_set_format(IMAGE_FORMAT);
+int image_init(PIMAGE_CTX, const size_t, const size_t, const IMAGE_MODEL, const IMAGE_FORMAT);
+int image_add_pixel(PIMAGE_CTX ctx, const uint8_t, const uint8_t, const uint8_t, const uint8_t);
+int image_set_pixel(PIMAGE_CTX ctx, const size_t, const size_t, const uint8_t, const uint8_t, const uint8_t, const uint8_t);
+int image_get_pixel(PIMAGE_CTX ctx,const size_t,const size_t, uint8_t const*, uint8_t const*, uint8_t const*, uint8_t const*);
+int image_get_filename(PIMAGE_CTX, char*, size_t, char*);
+int image_write(PIMAGE_CTX, FILE*);
+int image_set_library(char*);
 
-#define ADD_PIXEL(ctx,r,g,b) image_add_pixel((ctx),(r),(g),(b),0)
+#define ADD_PIXEL(ctx,r,g,b) image_add_pixel((ctx),(r),(g),(b),0xff)
 #define ADD_PIXELA(ctx,r,g,b,a) image_add_pixel((ctx),(r),(g),(b),(a))
 
 #endif
\ No newline at end of file
diff --git a/outputs.cc b/outputs.cc
index ca90da5..6425096 100644
--- a/outputs.cc
+++ b/outputs.cc
@@ -533,7 +533,7 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 	IMAGE_CTX ctx;
 	int success;
 
-	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB)) != 0){
+	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
 		fprintf(stderr,"Error initializing image\n");
 		exit(success);
 	}

From 6fecec8e4e369dfc7f54b3592c4d781b8ab85665 Mon Sep 17 00:00:00 2001
From: Gareth Evans <gareth.evans@contextis.co.uk>
Date: Thu, 2 Feb 2017 12:41:36 +0000
Subject: [PATCH 3/6] Add image_free to tidy-up

---
 image.cc   | 6 +++++-
 image.hh   | 1 +
 outputs.cc | 2 ++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/image.cc b/image.cc
index da67bef..ecee80d 100644
--- a/image.cc
+++ b/image.cc
@@ -106,7 +106,7 @@ int image_init(PIMAGE_CTX ctx, \
 	return success;
 }
 /*
- * image_add_pixel, image_set_pixel, image_get_pixel, image_write
+ * image_add_pixel, image_set_pixel, image_get_pixel, image_write, image_free
  * Various setters ad getters for assigning pixel data. image_write
  * takes an open file handle and writes image data to it.
  * These functions simply wrap the underlying format-specific functions
@@ -134,6 +134,10 @@ int image_write(PIMAGE_CTX ctx, FILE *fd){
 	if(ctx->initialized != 1) return EINVAL;
 	return dt->write(ctx,fd);
 }
+void image_free(PIMAGE_CTX ctx){
+	if(ctx->initialized != 1) return;
+	free(ctx->canvas);
+}
 
 /*
  * image_get_filename
diff --git a/image.hh b/image.hh
index 45437d0..67812b9 100644
--- a/image.hh
+++ b/image.hh
@@ -36,6 +36,7 @@ int image_set_pixel(PIMAGE_CTX ctx, const size_t, const size_t, const uint8_t, c
 int image_get_pixel(PIMAGE_CTX ctx,const size_t,const size_t, uint8_t const*, uint8_t const*, uint8_t const*, uint8_t const*);
 int image_get_filename(PIMAGE_CTX, char*, size_t, char*);
 int image_write(PIMAGE_CTX, FILE*);
+void image_free(PIMAGE_CTX);
 int image_set_library(char*);
 
 #define ADD_PIXEL(ctx,r,g,b) image_add_pixel((ctx),(r),(g),(b),0xff)
diff --git a/outputs.cc b/outputs.cc
index 6425096..b1b9202 100644
--- a/outputs.cc
+++ b/outputs.cc
@@ -749,6 +749,8 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 
 	fflush(fd);
 
+	image_free(&ctx);
+
 	if( filename != NULL ) {
 		fclose(fd);
 		fd = NULL;

From de3c4edc2f251d0bd273d46b4af970983f649bf8 Mon Sep 17 00:00:00 2001
From: Gareth Evans <gareth.evans@contextis.co.uk>
Date: Thu, 2 Feb 2017 12:51:03 +0000
Subject: [PATCH 4/6] Complete migration of models to image rendering engine

---
 outputs.cc | 199 +++++++++++++++++++++++++----------------------------
 1 file changed, 93 insertions(+), 106 deletions(-)

diff --git a/outputs.cc b/outputs.cc
index b1b9202..0c3df48 100644
--- a/outputs.cc
+++ b/outputs.cc
@@ -31,6 +31,13 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, z, x0 = 0, y0 = 0, loss, match;
 	double lat, lon, conversion, one_over_gamma, minwest;
 	FILE *fd;
+	IMAGE_CTX ctx;
+	int success;
+
+	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
+		fprintf(stderr,"Error initializing image\n");
+		exit(success);
+	}
 
 	one_over_gamma = 1.0 / GAMMA;
 	conversion =
@@ -46,24 +53,11 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 			filename[strlen(filename) - 4] = 0;	/* Remove .qth */
 		}
 
-		y = strlen(filename);
-
-		if (y > 4) {
-			if (filename[y - 1] == 'm' && filename[y - 2] == 'p'
-			    && filename[y - 3] == 'p' && filename[y - 4] == '.')
-				y -= 4;
+		if(image_get_filename(&ctx,mapfile,sizeof(mapfile),filename) != 0){
+			fprintf(stderr,"Error creating file name\n");
+			exit(1);
 		}
 
-		for (x = 0; x < y; x++) {
-			mapfile[x] = filename[x];
-		}
-
-		mapfile[x] = '.';
-		mapfile[x + 1] = 'p';
-		mapfile[x + 2] = 'p';
-		mapfile[x + 3] = 'm';
-		mapfile[x + 4] = 0;
-
 		fd = fopen(mapfile,"wb");
 
 	} else {
@@ -88,7 +82,6 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 	east = (minwest < 180.0 ? -minwest : 360.0 - min_west);
 	west = (double)(max_west < 180 ? -max_west : 360 - max_west);
 
-	fprintf(fd, "P6\n%u %u\n255\n", width, (kml ? height : height + 30));
 	if (debug) {
 		fprintf(stderr, "\nWriting \"%s\" (%ux%u pixmap image)...\n",
 			filename != NULL ? mapfile : "to stdout", width, (kml ? height : height + 30));
@@ -161,11 +154,11 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 
 					if (red >= 180 && green <= 75
 					    && blue <= 75 && loss == 0)
-						fprintf(fd, "%c%c%c", 255 ^ red,
+						ADD_PIXEL(&ctx, 255 ^ red,
 							255 ^ green,
 							255 ^ blue);
 					else
-						fprintf(fd, "%c%c%c", 255, 0,
+						ADD_PIXEL(&ctx, 255, 0,
 							0);
 
 					cityorcounty = 1;
@@ -174,7 +167,7 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 				else if (mask & 4) {
 					/* County Boundaries: Black */
 
-					fprintf(fd, "%c%c%c", 0, 0, 0);
+					ADD_PIXEL(&ctx, 0, 0, 0);
 
 					cityorcounty = 1;
 				}
@@ -185,15 +178,14 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 						&& loss >
 						abs(contour_threshold))) {
 						if (ngs)	/* No terrain */
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx, 
 								255, 255, 255);
 						else {
 							/* Display land or sea elevation */
 
 							if (dem[indx].
 							    data[x0][y0] == 0)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									0, 0,
 									170);
 							else {
@@ -201,8 +193,7 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 								    (unsigned)
 								    (0.5 +
 								     pow((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									terrain,
 									terrain,
 									terrain);
@@ -215,7 +206,7 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 
 						if (red != 0 || green != 0
 						    || blue != 0)
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx, 
 								red, green,
 								blue);
 
@@ -223,8 +214,7 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 
 							if (dem[indx].
 							    data[x0][y0] == 0)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									0, 0,
 									170);
 							else {
@@ -233,8 +223,7 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 								    (unsigned)
 								    (0.5 +
 								     pow((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									terrain,
 									terrain,
 									terrain);
@@ -248,11 +237,18 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 				/* We should never get here, but if */
 				/* we do, display the region as black */
 
-				fprintf(fd, "%c%c%c", 0, 0, 0);
+				ADD_PIXEL(&ctx, 0, 0, 0);
 			}
 		}
 	}
 
+	if((success = image_write(&ctx,fd)) != 0){
+		fprintf(stderr,"Error writing image\n");
+		exit(success);
+	}
+
+	image_free(&ctx);
+
 	if( filename != NULL ) {
 		fclose(fd);
 		fd = NULL;
@@ -275,6 +271,13 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, z = 1, x0 = 0, y0 = 0, signal, match;
 	double conversion, one_over_gamma, lat, lon, minwest;
 	FILE *fd;
+	IMAGE_CTX ctx;
+	int success;
+
+	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
+		fprintf(stderr,"Error initializing image\n");
+		exit(success);
+	}
 
 	one_over_gamma = 1.0 / GAMMA;
 	conversion =
@@ -290,24 +293,11 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 			filename[strlen(filename) - 4] = 0;	/* Remove .qth */
 		}
 
-		y = strlen(filename);
-
-		if (y > 4) {
-			if (filename[y - 1] == 'm' && filename[y - 2] == 'p'
-			    && filename[y - 3] == 'p' && filename[y - 4] == '.')
-				y -= 4;
+		if(image_get_filename(&ctx,mapfile,sizeof(mapfile),filename) != 0){
+			fprintf(stderr,"Error creating file name\n");
+			exit(1);
 		}
 
-		for (x = 0; x < y; x++) {
-			mapfile[x] = filename[x];
-		}
-
-		mapfile[x] = '.';
-		mapfile[x + 1] = 'p';
-		mapfile[x + 2] = 'p';
-		mapfile[x + 3] = 'm';
-		mapfile[x + 4] = 0;
-
 		fd = fopen(mapfile,"wb");
 
 	} else {
@@ -329,7 +319,6 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 	east = (minwest < 180.0 ? -minwest : 360.0 - min_west);
 	west = (double)(max_west < 180 ? -max_west : 360 - max_west);
 
-	fprintf(fd, "P6\n%u %u\n255\n", width, (kml ? height : height + 30));
 	if (debug) {
 		fprintf(stderr, "\nWriting \"%s\" (%ux%u pixmap image)...\n",
 			filename != NULL ? mapfile : "to stdout", width, (kml ? height : height + 30));
@@ -403,11 +392,11 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 
 					if (red >= 180 && green <= 75
 					    && blue <= 75)
-						fprintf(fd, "%c%c%c", 255 ^ red,
+						ADD_PIXEL(&ctx, 255 ^ red,
 							255 ^ green,
 							255 ^ blue);
 					else
-						fprintf(fd, "%c%c%c", 255, 0,
+						ADD_PIXEL(&ctx, 255, 0,
 							0);
 
 					cityorcounty = 1;
@@ -416,7 +405,7 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 				else if (mask & 4) {
 					/* County Boundaries: Black */
 
-					fprintf(fd, "%c%c%c", 0, 0, 0);
+					ADD_PIXEL(&ctx, 0, 0, 0);
 
 					cityorcounty = 1;
 				}
@@ -425,15 +414,14 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 					if (contour_threshold != 0
 					    && signal < contour_threshold) {
 						if (ngs)
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx, 
 								255, 255, 255);
 						else {
 							/* Display land or sea elevation */
 
 							if (dem[indx].
 							    data[x0][y0] == 0)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									0, 0,
 									170);
 							else {
@@ -441,8 +429,7 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 								    (unsigned)
 								    (0.5 +
 								     pow((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									terrain,
 									terrain,
 									terrain);
@@ -455,15 +442,14 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 
 						if (red != 0 || green != 0
 						    || blue != 0)
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx, 
 								red, green,
 								blue);
 
 						else {	/* terrain / sea-level */
 
 							if (ngs)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									255,
 									255,
 									255);
@@ -471,9 +457,7 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 								if (dem[indx].
 								    data[x0][y0]
 								    == 0)
-									fprintf
-									    (fd,
-									     "%c%c%c",
+									ADD_PIXEL(&ctx, 
 									     0,
 									     0,
 									     170);
@@ -486,9 +470,7 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 									     +
 									     pow
 									     ((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-									fprintf
-									    (fd,
-									     "%c%c%c",
+									ADD_PIXEL(&ctx, 
 									     terrain,
 									     terrain,
 									     terrain);
@@ -503,11 +485,18 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 				/* We should never get here, but if */
 				/* we do, display the region as black */
 
-				fprintf(fd, "%c%c%c", 0, 0, 0);
+				ADD_PIXEL(&ctx, 0, 0, 0);
 			}
 		}
 	}
 
+	if((success = image_write(&ctx,fd)) != 0){
+		fprintf(stderr,"Error writing image\n");
+		exit(success);
+	}
+
+	image_free(&ctx);
+
 	if( filename != NULL ) {
 		fclose(fd);
 		fd = NULL;
@@ -773,6 +762,13 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, x0 = 0, y0 = 0;
 	double conversion, one_over_gamma, lat, lon, minwest;
 	FILE *fd;
+	IMAGE_CTX ctx;
+	int success;
+
+	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
+		fprintf(stderr,"Error initializing image\n");
+		exit(success);
+	}
 
 	one_over_gamma = 1.0 / GAMMA;
 	conversion =
@@ -786,24 +782,11 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 			filename[strlen(filename) - 4] = 0;	/* Remove .qth */
 		}
 
-		y = strlen(filename);
-
-		if (y > 4) {
-			if (filename[y - 1] == 'm' && filename[y - 2] == 'p'
-			    && filename[y - 3] == 'p' && filename[y - 4] == '.')
-				y -= 4;
+		if(image_get_filename(&ctx,mapfile,sizeof(mapfile),filename) != 0){
+			fprintf(stderr,"Error creating file name\n");
+			exit(1);
 		}
 
-		for (x = 0; x < y; x++) {
-			mapfile[x] = filename[x];
-		}
-
-		mapfile[x] = '.';
-		mapfile[x + 1] = 'p';
-		mapfile[x + 2] = 'p';
-		mapfile[x + 3] = 'm';
-		mapfile[x + 4] = 0;
-
 		fd = fopen(mapfile,"wb");
 
 	} else {
@@ -825,7 +808,6 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 	east = (minwest < 180.0 ? -minwest : 360.0 - min_west);
 	west = (double)(max_west < 180 ? -max_west : 360 - max_west);
 
-	fprintf(fd, "P6\n%u %u\n255\n", width, (kml ? height : height + 30));
 	if (debug) {
 		fprintf(stderr, "\nWriting \"%s\" (%ux%u pixmap image)...\n",
 			filename != NULL ? mapfile : "to stdout", width, (kml ? height : height + 30));
@@ -862,114 +844,113 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 
 				if (mask & 2)
 					/* Text Labels: Red */
-					fprintf(fd, "%c%c%c", 255, 0, 0);
+					ADD_PIXEL(&ctx, 255, 0, 0);
 
 				else if (mask & 4)
 					/* County Boundaries: Light Cyan */
-					fprintf(fd, "%c%c%c", 128, 128, 255);
+					ADD_PIXEL(&ctx, 128, 128, 255);
 
 				else
 					switch (mask & 57) {
 					case 1:
 						/* TX1: Green */
-						fprintf(fd, "%c%c%c", 0, 255,
+						ADD_PIXEL(&ctx, 0, 255,
 							0);
 						break;
 
 					case 8:
 						/* TX2: Cyan */
-						fprintf(fd, "%c%c%c", 0, 255,
+						ADD_PIXEL(&ctx, 0, 255,
 							255);
 						break;
 
 					case 9:
 						/* TX1 + TX2: Yellow */
-						fprintf(fd, "%c%c%c", 255, 255,
+						ADD_PIXEL(&ctx, 255, 255,
 							0);
 						break;
 
 					case 16:
 						/* TX3: Medium Violet */
-						fprintf(fd, "%c%c%c", 147, 112,
+						ADD_PIXEL(&ctx, 147, 112,
 							219);
 						break;
 
 					case 17:
 						/* TX1 + TX3: Pink */
-						fprintf(fd, "%c%c%c", 255, 192,
+						ADD_PIXEL(&ctx, 255, 192,
 							203);
 						break;
 
 					case 24:
 						/* TX2 + TX3: Orange */
-						fprintf(fd, "%c%c%c", 255, 165,
+						ADD_PIXEL(&ctx, 255, 165,
 							0);
 						break;
 
 					case 25:
 						/* TX1 + TX2 + TX3: Dark Green */
-						fprintf(fd, "%c%c%c", 0, 100,
+						ADD_PIXEL(&ctx, 0, 100,
 							0);
 						break;
 
 					case 32:
 						/* TX4: Sienna 1 */
-						fprintf(fd, "%c%c%c", 255, 130,
+						ADD_PIXEL(&ctx, 255, 130,
 							71);
 						break;
 
 					case 33:
 						/* TX1 + TX4: Green Yellow */
-						fprintf(fd, "%c%c%c", 173, 255,
+						ADD_PIXEL(&ctx, 173, 255,
 							47);
 						break;
 
 					case 40:
 						/* TX2 + TX4: Dark Sea Green 1 */
-						fprintf(fd, "%c%c%c", 193, 255,
+						ADD_PIXEL(&ctx, 193, 255,
 							193);
 						break;
 
 					case 41:
 						/* TX1 + TX2 + TX4: Blanched Almond */
-						fprintf(fd, "%c%c%c", 255, 235,
+						ADD_PIXEL(&ctx, 255, 235,
 							205);
 						break;
 
 					case 48:
 						/* TX3 + TX4: Dark Turquoise */
-						fprintf(fd, "%c%c%c", 0, 206,
+						ADD_PIXEL(&ctx, 0, 206,
 							209);
 						break;
 
 					case 49:
 						/* TX1 + TX3 + TX4: Medium Spring Green */
-						fprintf(fd, "%c%c%c", 0, 250,
+						ADD_PIXEL(&ctx, 0, 250,
 							154);
 						break;
 
 					case 56:
 						/* TX2 + TX3 + TX4: Tan */
-						fprintf(fd, "%c%c%c", 210, 180,
+						ADD_PIXEL(&ctx, 210, 180,
 							140);
 						break;
 
 					case 57:
 						/* TX1 + TX2 + TX3 + TX4: Gold2 */
-						fprintf(fd, "%c%c%c", 238, 201,
+						ADD_PIXEL(&ctx, 238, 201,
 							0);
 						break;
 
 					default:
 						if (ngs)	/* No terrain */
-							fprintf(fd, "%c%c%c",
+							ADD_PIXEL(&ctx, 
 								255, 255, 255);
 						else {
 							/* Sea-level: Medium Blue */
 							if (dem[indx].
 							    data[x0][y0] == 0)
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									0, 0,
 									170);
 							else {
@@ -978,8 +959,7 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 								    (unsigned)
 								    (0.5 +
 								     pow((double)(dem[indx].data[x0][y0] - min_elevation), one_over_gamma) * conversion);
-								fprintf(fd,
-									"%c%c%c",
+								ADD_PIXEL(&ctx, 
 									terrain,
 									terrain,
 									terrain);
@@ -992,11 +972,18 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 				/* We should never get here, but if */
 				/* we do, display the region as black */
 
-				fprintf(fd, "%c%c%c", 0, 0, 0);
+				ADD_PIXEL(&ctx, 0, 0, 0);
 			}
 		}
 	}
 
+	if((success = image_write(&ctx,fd)) != 0){
+		fprintf(stderr,"Error writing image\n");
+		exit(success);
+	}
+
+	image_free(&ctx);
+
 	if( filename != NULL) {
 		fclose(fd);
 		fd = NULL;

From 8d483d9b6e69ce5c3a61739df648494656ddb5d6 Mon Sep 17 00:00:00 2001
From: Gareth Evans <gareth.evans@contextis.co.uk>
Date: Fri, 3 Feb 2017 11:54:50 +0000
Subject: [PATCH 5/6] Tidy up and typedef structs for ease of maintenance

---
 image-ppm.cc | 10 ++++----
 image-ppm.hh | 16 +++++++++---
 image.cc     | 69 +++++++++++++++++++---------------------------------
 image.hh     | 56 ++++++++++++++++++++++++++----------------
 outputs.cc   |  8 +++---
 5 files changed, 81 insertions(+), 78 deletions(-)

diff --git a/image-ppm.cc b/image-ppm.cc
index a9d8044..8249011 100644
--- a/image-ppm.cc
+++ b/image-ppm.cc
@@ -4,7 +4,7 @@
 #include <errno.h>
 #include "image.hh"
 
-int ppm_init(PIMAGE_CTX ctx){
+int ppm_init(image_ctx_t *ctx){
 	size_t buf_size;
 
 	/* Perform simple sanity checking */
@@ -12,7 +12,7 @@ int ppm_init(PIMAGE_CTX ctx){
 		return EINVAL;
 	ctx->model = IMAGE_RGB; //Override this as we only support RGB
 	ctx->format = IMAGE_PPM;
-	ctx->extension = ".ppm";
+	ctx->extension = (char*)".ppm";
 
 	buf_size = ctx->width * ctx->height * RGB_SIZE;
 
@@ -25,7 +25,7 @@ int ppm_init(PIMAGE_CTX ctx){
 	return 0;
 }
 
-int ppm_add_pixel(PIMAGE_CTX ctx,const uint8_t r,const uint8_t g,const uint8_t b,const uint8_t a){
+int ppm_add_pixel(image_ctx_t *ctx,const uint8_t r,const uint8_t g,const uint8_t b,const uint8_t a){
 	register uint8_t* next;
 
 	next = ctx->next_pixel;
@@ -39,12 +39,12 @@ int ppm_add_pixel(PIMAGE_CTX ctx,const uint8_t r,const uint8_t g,const uint8_t b
 	return 0;
 }
 
-int ppm_get_pixel(PIMAGE_CTX ctx,const size_t x,const size_t y,const uint8_t *r,const uint8_t *g,const uint8_t *b,const uint8_t *a){
+int ppm_get_pixel(image_ctx_t *ctx,const size_t x,const size_t y,const uint8_t *r,const uint8_t *g,const uint8_t *b,const uint8_t *a){
 	/* STUB */
 	return 0;
 }
 
-int ppm_write(PIMAGE_CTX ctx, FILE* fd){
+int ppm_write(image_ctx_t *ctx, FILE* fd){
 	size_t written;
 	size_t count;
 
diff --git a/image-ppm.hh b/image-ppm.hh
index 4831f0a..dfe007b 100644
--- a/image-ppm.hh
+++ b/image-ppm.hh
@@ -4,10 +4,18 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdio.h>
+#include "image.hh"
 
-int ppm_init(PIMAGE_CTX ctx);
-int ppm_add_pixel(PIMAGE_CTX ctx,const uint8_t r,const uint8_t g,const uint8_t b,const uint8_t a);
-int ppm_get_pixel(PIMAGE_CTX ctx,const size_t x,const size_t y,const uint8_t *r,const uint8_t *g,const uint8_t *b,const uint8_t *a);
-int ppm_write(PIMAGE_CTX ctx, FILE* fd);
+int ppm_init(image_ctx_t *ctx);
+int ppm_add_pixel(image_ctx_t *ctx,const uint8_t r,const uint8_t g,const uint8_t b,const uint8_t a);
+int ppm_get_pixel(image_ctx_t *ctx,const size_t x,const size_t y,const uint8_t *r,const uint8_t *g,const uint8_t *b,const uint8_t *a);
+int ppm_write(image_ctx_t *ctx, FILE* fd);
+
+image_dispatch_table_t ppm_dt = {\
+	.init 		= ppm_init, \
+	.add_pixel 	= ppm_add_pixel, \
+	.get_pixel	= ppm_get_pixel, \
+	.write		= ppm_write
+};
 
 #endif
\ No newline at end of file
diff --git a/image.cc b/image.cc
index ecee80d..c8e2098 100644
--- a/image.cc
+++ b/image.cc
@@ -14,22 +14,10 @@
 #include "image.hh"
 #include "image-ppm.hh"
 
-typedef int _init(PIMAGE_CTX);
-typedef int _add_pixel(PIMAGE_CTX,const uint8_t,const uint8_t,const uint8_t,const uint8_t);
-typedef int _get_pixel(PIMAGE_CTX,const size_t,const size_t,const uint8_t*,const uint8_t*,const uint8_t*,const uint8_t*);
-typedef int _write(PIMAGE_CTX,FILE*);
+int get_dt(image_dispatch_table_t *dt, int format);
+int load_library(image_dispatch_table_t *dt);
 
-int get_dt(struct image_dispatch_table *dt, IMAGE_FORMAT format);
-int load_library(struct image_dispatch_table *dt);
-
-struct image_dispatch_table{
-	_init *init;
-	_add_pixel *add_pixel;
-	_get_pixel *get_pixel;
-	_write *write;
-};
-
-static IMAGE_FORMAT default_format = IMAGE_PPM;
+static int default_format = IMAGE_PPM;
 char *dynamic_backend = NULL;
 
 /*
@@ -37,7 +25,7 @@ char *dynamic_backend = NULL;
  * Changes the default format for the next
  * uninitialized image canvas
  */
-int image_set_format(IMAGE_FORMAT format){
+int image_set_format(int format){
 	if(format <= IMAGE_DEFAULT || format >= IMAGE_FORMAT_MAX)
 		return EINVAL;
 	default_format = format;
@@ -49,14 +37,14 @@ int image_set_format(IMAGE_FORMAT format){
  * Initialize an image context. Must be called
  * before attempting to write any image data
  */
-int image_init(PIMAGE_CTX ctx, \
+int image_init(image_ctx_t *ctx, \
 				const size_t width, \
 				const size_t height, \
-				const IMAGE_MODEL model, \
-				const IMAGE_FORMAT format) {
+				const int model, \
+				const int format) {
 
 	int success = 0;
-	struct image_dispatch_table *dt;
+	image_dispatch_table_t *dt;
 
 	/* Perform some sanity checking on provided arguments */
 	if(ctx == NULL)
@@ -68,7 +56,7 @@ int image_init(PIMAGE_CTX ctx, \
 	if(format >= IMAGE_FORMAT_MAX || (format == IMAGE_LIBRARY && dynamic_backend == NULL))
 		return EINVAL;
 
-	memset(ctx,0x00,sizeof(IMAGE_CTX));
+	memset(ctx,0x00,sizeof(image_ctx_t));
 
 	/* Assign the initialize values to the processing context */
 	ctx->width = width;
@@ -80,7 +68,7 @@ int image_init(PIMAGE_CTX ctx, \
 		ctx->format = format;
 
 	/* Get the dispatch table for this image format */
-	dt = (struct image_dispatch_table*) calloc(1,sizeof(struct image_dispatch_table));
+	dt = (image_dispatch_table_t *) calloc(1,sizeof(image_dispatch_table_t));
 	if(dt == NULL){
 		fprintf(stderr,"Error allocating dispatch table\n");
 		return ENOMEM;
@@ -111,30 +99,26 @@ int image_init(PIMAGE_CTX ctx, \
  * takes an open file handle and writes image data to it.
  * These functions simply wrap the underlying format-specific functions
  */
-int image_add_pixel(PIMAGE_CTX ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
-	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+int image_add_pixel(image_ctx_t *ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
 	if(ctx->initialized != 1) return EINVAL;
-	return dt->add_pixel(ctx,r,g,b,a);
+	return ((image_dispatch_table_t*)ctx->_dt)->add_pixel(ctx,r,g,b,a);
 }
-int image_set_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
+int image_set_pixel(image_ctx_t *ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
 	size_t block_size;
 	if(ctx->initialized != 1) return EINVAL;
 	block_size = ctx->model == IMAGE_RGB ? RGB_SIZE : RGBA_SIZE;
-	ctx->next_pixel = ctx->canvas + (x * block_size) + (ctx->width * block_size * y);
-	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
-	return dt->add_pixel(ctx,r,g,b,a);
+	ctx->next_pixel = ctx->canvas + PIXEL_OFFSET(x,y,ctx->width,block_size);
+	return ((image_dispatch_table_t*)ctx->_dt)->add_pixel(ctx,r,g,b,a);
 }
-int image_get_pixel(PIMAGE_CTX ctx, const size_t x, const size_t y, const uint8_t *r, const uint8_t *g, const uint8_t *b, const uint8_t *a){
-	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+int image_get_pixel(image_ctx_t *ctx, const size_t x, const size_t y, const uint8_t *r, const uint8_t *g, const uint8_t *b, const uint8_t *a){
 	if(ctx->initialized != 1) return EINVAL;
-	return dt->get_pixel(ctx,x,y,r,g,b,a);
+	return ((image_dispatch_table_t*)ctx->_dt)->get_pixel(ctx,x,y,r,g,b,a);
 }
-int image_write(PIMAGE_CTX ctx, FILE *fd){
-	struct image_dispatch_table *dt = (struct image_dispatch_table*)ctx->_dt;
+int image_write(image_ctx_t *ctx, FILE *fd){
 	if(ctx->initialized != 1) return EINVAL;
-	return dt->write(ctx,fd);
+	return ((image_dispatch_table_t*)ctx->_dt)->write(ctx,fd);
 }
-void image_free(PIMAGE_CTX ctx){
+void image_free(image_ctx_t *ctx){
 	if(ctx->initialized != 1) return;
 	free(ctx->canvas);
 }
@@ -145,7 +129,7 @@ void image_free(PIMAGE_CTX ctx){
  * by the user. If the extension is already correct, return
  * that; if not append if there is space
  */
-int image_get_filename(PIMAGE_CTX ctx, char *out, size_t len_out, char *in){
+int image_get_filename(image_ctx_t *ctx, char *out, size_t len_out, char *in){
 	size_t len_src;
 	size_t len_ext;
 	int success = 0;
@@ -188,16 +172,13 @@ int image_get_filename(PIMAGE_CTX ctx, char *out, size_t len_out, char *in){
  * Load the dispatch table for the specified image
  * format. Currently only pixmap supported.
  */
-int get_dt(struct image_dispatch_table *dt, IMAGE_FORMAT format){
+int get_dt(image_dispatch_table_t *dt, int format){
 	int success = 0;
 
-	memset((void*)dt,0x00,sizeof(struct image_dispatch_table));
+	memset((void*)dt,0x00,sizeof(image_dispatch_table_t));
 	switch(format){
 		case IMAGE_PPM:
-			dt->init = ppm_init;
-			dt->add_pixel = ppm_add_pixel;
-			dt->get_pixel = ppm_get_pixel;
-			dt->write = ppm_write;
+			*dt = ppm_dt;
 			break;
 		case IMAGE_LIBRARY:
 			success = load_library(dt);
@@ -248,7 +229,7 @@ char* image_get_library(){
  * Load an external library to perform image processing
  * It must be a custom compatible library
  */
-int load_library(struct image_dispatch_table *dt){
+int load_library(image_dispatch_table_t *dt){
 	void *hndl;
 	int success = 0;
 
diff --git a/image.hh b/image.hh
index 67812b9..fa456ef 100644
--- a/image.hh
+++ b/image.hh
@@ -6,40 +6,54 @@
 #define RGB_SIZE  3
 #define RGBA_SIZE 4
 
-typedef enum _IMAGE_FORMAT{	IMAGE_DEFAULT = 0, \
-							IMAGE_PPM, \
-							IMAGE_LIBRARY, \
-							IMAGE_FORMAT_MAX \
-						} IMAGE_FORMAT;
+enum _image_format{	IMAGE_DEFAULT = 0, \
+					IMAGE_PPM, \
+					IMAGE_LIBRARY, \
+					IMAGE_FORMAT_MAX \
+				};
 
-typedef enum _IMAGE_MODEL{	IMAGE_RGB, \
-							IMAGE_RGBA, \
-							IMAGE_MODEL_MAX
-						} IMAGE_MODEL;
+enum _image_model{	IMAGE_RGB, \
+					IMAGE_RGBA, \
+					IMAGE_MODEL_MAX
+				};
 
-typedef struct _IMAGE_CTX{
+typedef struct _image_ctx{
 	size_t width;
 	size_t height;
-	IMAGE_MODEL model;
-	IMAGE_FORMAT format;
+	int model;
+	int format;
 	uint8_t *canvas;
 	uint8_t *next_pixel;
 	uint32_t initialized;
 	char *extension;
 	void *_dt;
-} IMAGE_CTX, *PIMAGE_CTX;
+} image_ctx_t, *pimage_ctx_t;
 
-int image_set_format(IMAGE_FORMAT);
-int image_init(PIMAGE_CTX, const size_t, const size_t, const IMAGE_MODEL, const IMAGE_FORMAT);
-int image_add_pixel(PIMAGE_CTX ctx, const uint8_t, const uint8_t, const uint8_t, const uint8_t);
-int image_set_pixel(PIMAGE_CTX ctx, const size_t, const size_t, const uint8_t, const uint8_t, const uint8_t, const uint8_t);
-int image_get_pixel(PIMAGE_CTX ctx,const size_t,const size_t, uint8_t const*, uint8_t const*, uint8_t const*, uint8_t const*);
-int image_get_filename(PIMAGE_CTX, char*, size_t, char*);
-int image_write(PIMAGE_CTX, FILE*);
-void image_free(PIMAGE_CTX);
+typedef int _init(image_ctx_t*);
+typedef int _add_pixel(image_ctx_t*,const uint8_t,const uint8_t,const uint8_t,const uint8_t);
+typedef int _get_pixel(image_ctx_t*,const size_t,const size_t,const uint8_t*,const uint8_t*,const uint8_t*,const uint8_t*);
+typedef int _write(image_ctx_t*,FILE*);
+
+typedef struct _image_dispatch_table{
+	_init *init;
+	_add_pixel *add_pixel;
+	_get_pixel *get_pixel;
+	_write *write;
+} image_dispatch_table_t;
+
+int image_set_format(int);
+int image_init(image_ctx_t*, const size_t, const size_t, const int, const int);
+int image_add_pixel(image_ctx_t* ctx, const uint8_t, const uint8_t, const uint8_t, const uint8_t);
+int image_set_pixel(image_ctx_t* ctx, const size_t, const size_t, const uint8_t, const uint8_t, const uint8_t, const uint8_t);
+int image_get_pixel(image_ctx_t* ctx,const size_t,const size_t, uint8_t const*, uint8_t const*, uint8_t const*, uint8_t const*);
+int image_get_filename(image_ctx_t*, char*, size_t, char*);
+int image_write(image_ctx_t*, FILE*);
+void image_free(image_ctx_t*);
 int image_set_library(char*);
 
 #define ADD_PIXEL(ctx,r,g,b) image_add_pixel((ctx),(r),(g),(b),0xff)
 #define ADD_PIXELA(ctx,r,g,b,a) image_add_pixel((ctx),(r),(g),(b),(a))
 
+#define PIXEL_OFFSET(x,y,width,pixel_size) (((x) * (pixel_size)) + ((width) * (pixel_size) * (y)))
+
 #endif
\ No newline at end of file
diff --git a/outputs.cc b/outputs.cc
index 0c3df48..1dc278c 100644
--- a/outputs.cc
+++ b/outputs.cc
@@ -31,7 +31,7 @@ void DoPathLoss(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, z, x0 = 0, y0 = 0, loss, match;
 	double lat, lon, conversion, one_over_gamma, minwest;
 	FILE *fd;
-	IMAGE_CTX ctx;
+	image_ctx_t ctx;
 	int success;
 
 	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
@@ -271,7 +271,7 @@ void DoSigStr(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, z = 1, x0 = 0, y0 = 0, signal, match;
 	double conversion, one_over_gamma, lat, lon, minwest;
 	FILE *fd;
-	IMAGE_CTX ctx;
+	image_ctx_t ctx;
 	int success;
 
 	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
@@ -519,7 +519,7 @@ void DoRxdPwr(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, z = 1, x0 = 0, y0 = 0, dBm, match;
 	double conversion, one_over_gamma, lat, lon, minwest;
 	FILE *fd;
-	IMAGE_CTX ctx;
+	image_ctx_t ctx;
 	int success;
 
 	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){
@@ -762,7 +762,7 @@ void DoLOS(char *filename, unsigned char geo, unsigned char kml,
 	int indx, x, y, x0 = 0, y0 = 0;
 	double conversion, one_over_gamma, lat, lon, minwest;
 	FILE *fd;
-	IMAGE_CTX ctx;
+	image_ctx_t ctx;
 	int success;
 
 	if((success = image_init(&ctx, width, (kml ? height : height + 30), IMAGE_RGB, IMAGE_DEFAULT)) != 0){

From 594857c92c44f1f1c3acf3d807ef3e91b89c911b Mon Sep 17 00:00:00 2001
From: Gareth Evans <gareth.evans@contextis.co.uk>
Date: Fri, 3 Feb 2017 12:52:15 +0000
Subject: [PATCH 6/6] Various maintainability and speed improvements

---
 image-ppm.hh |  4 +++-
 image.cc     | 31 ++++++++++++++++++++++++-------
 image.hh     | 12 ++++++++----
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/image-ppm.hh b/image-ppm.hh
index dfe007b..fe40ede 100644
--- a/image-ppm.hh
+++ b/image-ppm.hh
@@ -14,8 +14,10 @@ int ppm_write(image_ctx_t *ctx, FILE* fd);
 image_dispatch_table_t ppm_dt = {\
 	.init 		= ppm_init, \
 	.add_pixel 	= ppm_add_pixel, \
+	.set_pixel	= NULL, \
 	.get_pixel	= ppm_get_pixel, \
-	.write		= ppm_write
+	.write		= ppm_write, \
+	.free		= NULL
 };
 
 #endif
\ No newline at end of file
diff --git a/image.cc b/image.cc
index c8e2098..1af4e72 100644
--- a/image.cc
+++ b/image.cc
@@ -17,6 +17,8 @@
 int get_dt(image_dispatch_table_t *dt, int format);
 int load_library(image_dispatch_table_t *dt);
 
+#define DISPATCH_TABLE(ctx) ((image_dispatch_table_t*)(ctx)->_dt)
+
 static int default_format = IMAGE_PPM;
 char *dynamic_backend = NULL;
 
@@ -101,26 +103,35 @@ int image_init(image_ctx_t *ctx, \
  */
 int image_add_pixel(image_ctx_t *ctx, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
 	if(ctx->initialized != 1) return EINVAL;
-	return ((image_dispatch_table_t*)ctx->_dt)->add_pixel(ctx,r,g,b,a);
+	return DISPATCH_TABLE(ctx)->add_pixel(ctx,r,g,b,a);
 }
 int image_set_pixel(image_ctx_t *ctx, const size_t x, const size_t y, const uint8_t r, const uint8_t g, const uint8_t b, const uint8_t a){
 	size_t block_size;
 	if(ctx->initialized != 1) return EINVAL;
+	/* Image format handlers have the option to specify a _set_pixel handler */
+	if(DISPATCH_TABLE(ctx)->set_pixel != NULL){
+		return DISPATCH_TABLE(ctx)->set_pixel(ctx,x,y,r,g,b,a);
+	}
 	block_size = ctx->model == IMAGE_RGB ? RGB_SIZE : RGBA_SIZE;
 	ctx->next_pixel = ctx->canvas + PIXEL_OFFSET(x,y,ctx->width,block_size);
-	return ((image_dispatch_table_t*)ctx->_dt)->add_pixel(ctx,r,g,b,a);
+	return DISPATCH_TABLE(ctx)->add_pixel(ctx,r,g,b,a);
 }
 int image_get_pixel(image_ctx_t *ctx, const size_t x, const size_t y, const uint8_t *r, const uint8_t *g, const uint8_t *b, const uint8_t *a){
 	if(ctx->initialized != 1) return EINVAL;
-	return ((image_dispatch_table_t*)ctx->_dt)->get_pixel(ctx,x,y,r,g,b,a);
+	if(DISPATCH_TABLE(ctx)->get_pixel != NULL)
+		return DISPATCH_TABLE(ctx)->get_pixel(ctx,x,y,r,g,b,a);
+	return ENOSYS;
 }
 int image_write(image_ctx_t *ctx, FILE *fd){
 	if(ctx->initialized != 1) return EINVAL;
-	return ((image_dispatch_table_t*)ctx->_dt)->write(ctx,fd);
+	return DISPATCH_TABLE(ctx)->write(ctx,fd);
 }
 void image_free(image_ctx_t *ctx){
 	if(ctx->initialized != 1) return;
-	free(ctx->canvas);
+	if(DISPATCH_TABLE(ctx)->free != NULL){
+		DISPATCH_TABLE(ctx)->free(ctx);
+	}
+	if(ctx->canvas != NULL) free(ctx->canvas);
 }
 
 /*
@@ -248,10 +259,16 @@ int load_library(image_dispatch_table_t *dt){
 	/* Perform symbol lookup */
 	if((dt->init = (_init*)dlsym(hndl,"lib_init")) == NULL ||
 		(dt->add_pixel = (_add_pixel*)dlsym(hndl,"lib_add_pixel")) == NULL ||
-		(dt->get_pixel = (_get_pixel*)dlsym(hndl,"lib_get_pixel")) == NULL ||
 		(dt->write = (_write*)dlsym(hndl,"lib_write")) == NULL){
 		fprintf(stderr,"Invalid image processing module specified\n\t%s",dlerror());
-		success = dlclose(hndl);
+		success = EINVAL;
+		(void) dlclose(hndl);
+	}
+	/* Lookup optional symbols, these can return NULL */
+	if(success == 0){
+		dt->get_pixel = (_get_pixel*)dlsym(hndl,"lib_get_pixel");
+		dt->set_pixel = (_set_pixel*)dlsym(hndl,"lib_set_pixel");
+		dt->free = (_free*)dlsym(hndl,"lib_free");
 	}
 
 	return success;
diff --git a/image.hh b/image.hh
index fa456ef..537b053 100644
--- a/image.hh
+++ b/image.hh
@@ -31,14 +31,18 @@ typedef struct _image_ctx{
 
 typedef int _init(image_ctx_t*);
 typedef int _add_pixel(image_ctx_t*,const uint8_t,const uint8_t,const uint8_t,const uint8_t);
+typedef int _set_pixel(image_ctx_t*,const size_t,const size_t,const uint8_t,const uint8_t,const uint8_t,const uint8_t);
 typedef int _get_pixel(image_ctx_t*,const size_t,const size_t,const uint8_t*,const uint8_t*,const uint8_t*,const uint8_t*);
 typedef int _write(image_ctx_t*,FILE*);
+typedef void _free(image_ctx_t*);
 
 typedef struct _image_dispatch_table{
-	_init *init;
-	_add_pixel *add_pixel;
-	_get_pixel *get_pixel;
-	_write *write;
+	_init		*init;
+	_add_pixel	*add_pixel;
+	_set_pixel	*set_pixel;
+	_get_pixel	*get_pixel;
+	_write		*write;
+	_free		*free;
 } image_dispatch_table_t;
 
 int image_set_format(int);