pngquant_error pngquant_file(const char *filename, const char *outname, struct pngquant_options *options)
{
pngquant_error retval = SUCCESS;
verbose_printf(options, "%s:", filename);
liq_image *input_image = NULL;
png24_image input_image_rwpng = {};
bool keep_input_pixels = options->using_stdin && options->min_quality_limit; // original may need to be output to stdout
if (!retval) {
retval = read_image(options->liq, filename, options->using_stdin, &input_image_rwpng, &input_image, keep_input_pixels);
}
png8_image output_image = {};
if (!retval) {
verbose_printf(options, " read %luKB file corrected for gamma %2.1f",
(input_image_rwpng.file_size+1023UL)/1024UL, 1.0/input_image_rwpng.gamma);
// when using image as source of a fixed palette the palette is extracted using regular quantization
liq_result *remap = liq_quantize_image(options->liq, options->fixed_palette_image ? options->fixed_palette_image : input_image);
if (remap) {
liq_set_output_gamma(remap, 0.45455); // fixed gamma ~2.2 for the web. PNG can't store exact 1/2.2
liq_set_dithering_level(remap, options->floyd);
retval = prepare_output_image(remap, input_image, &output_image);
if (!retval) {
if (LIQ_OK != liq_write_remapped_image_rows(remap, input_image, output_image.row_pointers)) {
retval = OUT_OF_MEMORY_ERROR;
}
set_palette(remap, &output_image);
double palette_error = liq_get_quantization_error(remap);
if (palette_error >= 0) {
verbose_printf(options, " mapped image to new colors...MSE=%.3f (Q=%d)", palette_error, liq_get_quantization_quality(remap));
}
}
liq_result_destroy(remap);
} else {
retval = TOO_LOW_QUALITY;
}
}
if (!retval) {
output_image.fast_compression = options->fast_compression;
retval = write_image(&output_image, NULL, outname, options);
} else if (TOO_LOW_QUALITY == retval && options->using_stdin) {
// when outputting to stdout it'd be nasty to create 0-byte file
// so if quality is too low, output 24-bit original
pngquant_error write_retval = write_image(NULL, &input_image_rwpng, outname, options);
if (write_retval) retval = write_retval;
}
liq_image_destroy(input_image);
pngquant_output_image_free(&output_image);
free(input_image_rwpng.row_pointers);
free(input_image_rwpng.rgba_data);
return retval;
}
pngquant_error pngquant_file(const char *filename, const char *outname, struct pngquant_options *options)
{
pngquant_error retval = SUCCESS;
verbose_printf(options, "%s:", filename);
liq_image *input_image = NULL;
png24_image input_image_rwpng = {};
bool keep_input_pixels = options->skip_if_larger || (options->using_stdin && options->min_quality_limit); // original may need to be output to stdout
if (!retval) {
retval = read_image(options->liq, filename, options->using_stdin, &input_image_rwpng, &input_image, keep_input_pixels);
}
int quality_percent = 90; // quality on 0-100 scale, updated upon successful remap
png8_image output_image = {};
if (!retval) {
verbose_printf(options, " read %luKB file corrected for gamma %2.1f",
(input_image_rwpng.file_size+1023UL)/1024UL, 1.0/input_image_rwpng.gamma);
// when using image as source of a fixed palette the palette is extracted using regular quantization
liq_result *remap = liq_quantize_image(options->liq, options->fixed_palette_image ? options->fixed_palette_image : input_image);
if (remap) {
liq_set_output_gamma(remap, 0.45455); // fixed gamma ~2.2 for the web. PNG can't store exact 1/2.2
liq_set_dithering_level(remap, options->floyd);
retval = prepare_output_image(remap, input_image, &output_image);
if (!retval) {
if (LIQ_OK != liq_write_remapped_image_rows(remap, input_image, output_image.row_pointers)) {
retval = OUT_OF_MEMORY_ERROR;
}
set_palette(remap, &output_image);
double palette_error = liq_get_quantization_error(remap);
if (palette_error >= 0) {
quality_percent = liq_get_quantization_quality(remap);
verbose_printf(options, " mapped image to new colors...MSE=%.3f (Q=%d)", palette_error, quality_percent);
}
}
liq_result_destroy(remap);
} else {
retval = TOO_LOW_QUALITY;
}
}
if (!retval) {
if (options->skip_if_larger) {
// this is very rough approximation, but generally avoid losing more quality than is gained in file size.
// Quality is squared, because even greater savings are needed to justify big quality loss.
double quality = quality_percent/100.0;
output_image.maximum_file_size = input_image_rwpng.file_size * quality*quality;
}
output_image.fast_compression = options->fast_compression;
retval = write_image(&output_image, NULL, outname, options);
if (TOO_LARGE_FILE == retval) {
verbose_printf(options, " file exceeded expected size of %luKB", (unsigned long)output_image.maximum_file_size/1024UL);
}
}
if (TOO_LARGE_FILE == retval || (TOO_LOW_QUALITY == retval && options->using_stdin)) {
// when outputting to stdout it'd be nasty to create 0-byte file
// so if quality is too low, output 24-bit original
if (keep_input_pixels) {
pngquant_error write_retval = write_image(NULL, &input_image_rwpng, outname, options);
if (write_retval) retval = write_retval;
}
}
liq_image_destroy(input_image);
pngquant_output_image_free(&output_image);
free(input_image_rwpng.row_pointers);
free(input_image_rwpng.rgba_data);
return retval;
}
