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Add memory buffer output option

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This commit is contained in:
David Baer
2021-05-08 17:52:32 -04:00
parent 70f164daee
commit 8f88b7ee30
2 changed files with 79 additions and 0 deletions
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1
include/mazemaker.h
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@@ -25,5 +25,6 @@ typedef enum {
void mazemaker_generate_maze(int width, int height, mazegrid_t* result);
void mazemaker_free_maze(mazegrid_t* maze);
int mazemaker_maze_to_png(mazegrid_t const* maze, char const* filename);
int mazemaker_maze_to_png_mem(mazegrid_t const* maze, size_t* len, uint8_t** buf);
#endif // !def(_MAZEMAKER_H)

78
lib/image.c
View File

@@ -16,6 +16,11 @@ typedef struct {
int w, h;
} img_data_t;
struct mem_encode {
uint8_t *buffer;
size_t size;
};
static void setPixel(img_data_t* img, int x, int y, char v) {
//fprintf(stderr, "setPixel(img, %d, %d, %d)\n", x, y, v);
assert((x < img->w) && (y < img->h));
@@ -150,3 +155,76 @@ exit:
if (img != NULL) freeImageData(img);
return code;
}
static void append_png_data(png_structp png_ptr, png_bytep data, png_size_t length) {
struct mem_encode* p = (struct mem_encode*)png_get_io_ptr(png_ptr);
size_t nsize = p->size + length;
if (p->buffer)
p->buffer = realloc(p->buffer, nsize);
else
p->buffer = malloc(nsize);
if (!p->buffer)
png_error(png_ptr, "Write error");
memcpy(p->buffer + p->size, data, length);
p->size += length;
}
static void png_no_flush(png_structp png_ptr) {
/* noop */
}
int mazemaker_maze_to_png_mem(mazegrid_t const* g, size_t* len, uint8_t** buf) {
int code = 1;
img_data_t* img = gridToImageData(g);
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
struct mem_encode menc = { .buffer = NULL, .size = 0 };
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (png_ptr == NULL) {
fprintf(stderr, "Could not allocate PNG write struct.\n");
code = 0;
goto exit;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
fprintf(stderr, "Could not allocate PNG info struct.\n");
code = 0;
goto exit;
}
if (setjmp(png_jmpbuf(png_ptr))) {
fprintf(stderr, "Error during PNG creation.\n");
code = 0;
goto exit;
}
png_set_write_fn(png_ptr, &menc, append_png_data, png_no_flush);
// Write header (8 bit color depth)
png_set_IHDR(png_ptr, info_ptr, img->w, img->h,
8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_write_info(png_ptr, info_ptr);
writeImageData(img, png_ptr);
png_write_end(png_ptr, NULL);
*len = menc.size;
*buf = menc.buffer;
exit:
if (!code && menc.buffer) {
free(menc.buffer);
}
if (info_ptr != NULL) {
png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
png_destroy_info_struct(png_ptr, &info_ptr);
}
if (png_ptr != NULL) png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
if (img != NULL) freeImageData(img);
return code;
}