Use libpng for writing of PNGs (currently only works with RGB/RGBA surfaces, and only writes RGB)

This commit is contained in:
Michael Jumper 2012-04-01 20:19:12 -07:00
parent bd864f3f8f
commit 3cae4f016f

View File

@ -54,6 +54,8 @@
#include <pngstruct.h>
#endif
#include <png.h>
#include <cairo/cairo.h>
#include <sys/types.h>
@ -108,12 +110,18 @@ typedef struct __guac_socket_write_png_data {
int buffer_size;
int data_size;
}
__guac_socket_write_png_data;
} __guac_socket_write_png_data;
cairo_status_t __guac_socket_write_png(void* closure, const unsigned char* data, unsigned int length) {
void __guac_socket_write_png(png_structp png,
png_bytep data, png_size_t length) {
__guac_socket_write_png_data* png_data = (__guac_socket_write_png_data*) closure;
/* Get png buffer structure */
__guac_socket_write_png_data* png_data;
#ifdef HAVE_PNG_GET_IO_PTR
png_data = (__guac_socket_write_png_data*) png_get_io_ptr(png);
#else
png_data = (__guac_socket_write_png_data*) png->io_ptr;
#endif
/* Calculate next buffer size */
int next_size = png_data->data_size + length;
@ -137,26 +145,111 @@ cairo_status_t __guac_socket_write_png(void* closure, const unsigned char* data,
memcpy(png_data->buffer + png_data->data_size, data, length);
png_data->data_size += length;
return CAIRO_STATUS_SUCCESS;
}
void __guac_socket_flush_png(png_structp png) {
/* Dummy function */
}
int __guac_socket_write_length_png(guac_socket* socket, cairo_surface_t* surface) {
png_structp png;
png_infop png_info;
png_byte** png_rows;
int x, y;
__guac_socket_write_png_data png_data;
int base64_length;
/* Write surface */
/* Get image surface properties and data */
/*cairo_format_t format = cairo_image_surface_get_format(surface);*/
int width = cairo_image_surface_get_width(surface);
int height = cairo_image_surface_get_height(surface);
int stride = cairo_image_surface_get_stride(surface);
unsigned char* data = cairo_image_surface_get_data(surface);
/* Flush pending operations to surface */
cairo_surface_flush(surface);
/* If not an image surface, fail */
if (data == NULL) {
return -1; /* FIXME: Set guac_error, etc? */
}
/* Copy data from surface into PNG data */
png_rows = (png_byte**) malloc(sizeof(png_byte*) * height);
for (y=0; y<height; y++) {
/* Allocate new PNG row */
png_byte* row = (png_byte*) malloc(sizeof(png_byte) * width * 3);
png_rows[y] = row;
/* Copy data from surface into current row */
for (x=0; x<width; x++) {
row[3*x] = data[4*x+2];
row[3*x+1] = data[4*x+1];
row[3*x+2] = data[4*x];
}
/* Advance to next data row */
data += stride;
}
/* Set up PNG writer */
png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png) {
return -1; /* FIXME: Set guac_error, etc? */
}
png_info = png_create_info_struct(png);
if (!png_info) {
png_destroy_write_struct(&png, NULL);
return -1; /* FIXME: Set guac_error, etc? */
}
/* Set error handler */
if (setjmp(png_jmpbuf(png))) {
png_destroy_write_struct(&png, &png_info);
return -1; /* FIXME: Set guac_error, etc? */
}
/* Set up buffer structure */
png_data.socket = socket;
png_data.buffer_size = 8192;
png_data.buffer = malloc(png_data.buffer_size);
png_data.data_size = 0;
if (cairo_surface_write_to_png_stream(surface, __guac_socket_write_png, &png_data) != CAIRO_STATUS_SUCCESS) {
return -1;
}
/* Set up writer */
png_set_write_fn(png, &png_data,
__guac_socket_write_png,
__guac_socket_flush_png);
/* Write image info */
png_set_IHDR(
png,
png_info,
width,
height,
8,
PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT,
PNG_FILTER_TYPE_DEFAULT
);
/* Write image */
png_set_rows(png, png_info, png_rows);
png_write_png(png, png_info, PNG_TRANSFORM_IDENTITY, NULL);
/* Finish write */
png_destroy_write_struct(&png, &png_info);
/* Free PNG data */
for (y=0; y<height; y++)
free(png_rows[y]);
free(png_rows);
base64_length = (png_data.data_size + 2) / 3 * 4;