gifwedge.c

/*****************************************************************************

gifwedge - create a GIF test pattern

SPDX-License-Identifier: MIT

*****************************************************************************/

#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "getarg.h"
#include "gif_lib.h"

#define PROGRAM_NAME "gifwedge"

#define DEFAULT_WIDTH 640
#define DEFAULT_HEIGHT 350

#define DEFAULT_NUM_LEVELS 16 /* Number of colors to gen the image. */

static char *VersionStr = PROGRAM_NAME VERSION_COOKIE
    "	Gershon Elber,	" __DATE__ ",   " __TIME__ "\n"
    "(C) Copyright 1989 Gershon Elber.\n";
static char *CtrlStr = PROGRAM_NAME " v%- l%-#Lvls!d s%-Width|Height!d!d h%-";

static int NumLevels = DEFAULT_NUM_LEVELS, ImageWidth = DEFAULT_WIDTH,
           ImageHeight = DEFAULT_HEIGHT;

/******************************************************************************
 Interpret the command line and scan the given GIF file.
******************************************************************************/
int main(int argc, char **argv) {
	int i, j, l, c, LevelStep, LogNumLevels, ErrorCode, Count = 0;
	bool Error, LevelsFlag = false, SizeFlag = false, HelpFlag = false,
	            GifNoisyPrint = false;
	GifRowType Line;
	ColorMapObject *ColorMap;
	GifFileType *GifFile;

	if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifNoisyPrint, &LevelsFlag,
	                       &NumLevels, &SizeFlag, &ImageWidth, &ImageHeight,
	                       &HelpFlag)) != false) {
		GAPrintErrMsg(Error);
		GAPrintHowTo(CtrlStr);
		exit(EXIT_FAILURE);
	}

	if (HelpFlag) {
		(void)fprintf(stderr, VersionStr, GIFLIB_MAJOR, GIFLIB_MINOR);
		GAPrintHowTo(CtrlStr);
		exit(EXIT_SUCCESS);
	}

	/* Make sure the number of levels is power of 2 (up to 32 levels.). */
	for (i = 1; i < 6; i++) {
		if (NumLevels == (1 << i)) {
			break;
		}
	}
	if (i == 6) {
		GIF_EXIT("#Lvls (-l option) is not power of 2 up to 32.");
	}
	LogNumLevels = i + 3; /* Multiple by 8 (see below). */
	LevelStep = 256 / NumLevels;

	/* Make sure the image dimension is a multiple of NumLevels horizontally
	 */
	/* and 7 (White, Red, Green, Blue and Yellow Cyan Magenta) vertically.
	 */
	ImageWidth = (ImageWidth / NumLevels) * NumLevels;
	ImageHeight = (ImageHeight / 7) * 7;

	/* Open stdout for the output file: */
	if ((GifFile = EGifOpenFileHandle(1, &ErrorCode)) == NULL) {
		PrintGifError(ErrorCode);
		exit(EXIT_FAILURE);
	}

	/* Dump out screen description with given size and generated color map:
	 */
	/* The color map has 7 NumLevels colors for White, Red, Green and then
	 */
	/* The secondary colors Yellow Cyan and magenta. */
	if ((ColorMap = GifMakeMapObject(8 * NumLevels, NULL)) == NULL) {
		GIF_EXIT("Failed to allocate memory required, aborted.");
	}

	for (i = 0; i < 8; i++) { /* Set color map. */
		for (j = 0; j < NumLevels; j++) {
			l = LevelStep * j;
			c = i * NumLevels + j;
			ColorMap->Colors[c].Red =
			    (i == 0 || i == 1 || i == 4 || i == 6) * l;
			ColorMap->Colors[c].Green =
			    (i == 0 || i == 2 || i == 4 || i == 5) * l;
			ColorMap->Colors[c].Blue =
			    (i == 0 || i == 3 || i == 5 || i == 6) * l;
		}
	}

	if (EGifPutScreenDesc(GifFile, ImageWidth, ImageHeight, LogNumLevels, 0,
	                      ColorMap) == GIF_ERROR) {
		PrintGifError(GifFile->Error);
	}

	/* Dump out the image descriptor: */
	if (EGifPutImageDesc(GifFile, 0, 0, ImageWidth, ImageHeight, false,
	                     NULL) == GIF_ERROR) {

		PrintGifError(GifFile->Error);
		exit(EXIT_FAILURE);
	}

	GifQprintf("\n%s: Image 1 at (%d, %d) [%dx%d]:     ", PROGRAM_NAME,
	           GifFile->Image.Left, GifFile->Image.Top,
	           GifFile->Image.Width, GifFile->Image.Height);

	/* Allocate one scan line to be used for all image. */
	if ((Line = (GifRowType)malloc(sizeof(GifPixelType) * ImageWidth)) ==
	    NULL) {
		GIF_EXIT("Failed to allocate memory required, aborted.");
	}

	/* Dump the pixels: */
	for (c = 0; c < 7; c++) {
		for (i = 0, l = 0; i < NumLevels; i++) {
			for (j = 0; j < ImageWidth / NumLevels; j++) {
				Line[l++] = i + NumLevels * c;
			}
		}
		for (i = 0; i < ImageHeight / 7; i++) {
			if (EGifPutLine(GifFile, Line, ImageWidth) ==
			    GIF_ERROR) {
				PrintGifError(GifFile->Error);
				exit(EXIT_FAILURE);
			}
			GifQprintf("\b\b\b\b%-4d", Count++);
		}
	}

	if (EGifCloseFile(GifFile, &ErrorCode) == GIF_ERROR) {
		PrintGifError(ErrorCode);
		exit(EXIT_FAILURE);
	}

	return 0;
}

/* end */