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/*:*
* ggaze — JPEG XL loader backend (libjxl)
*
* Decodes JPEG XL (codestream or container) via libjxl's JxlDecoder into RGBA
* pixels, then wraps them in a GdkMemoryTexture. Honors EXIF orientation is
* not needed for JXL (orientation is handled in the container). Compiled only
* when meson feature `jxl` is enabled.
*
* Copyright (c) 2026 ggaze contributors
* SPDX-License-Identifier: GPL-3.0-or-later
*:*/
#include "../loader.h"
#include "../detect.h"
#include <gdk/gdk.h>
#include <gio/gio.h>
#include <jxl/decode.h>
#include <jxl/types.h>
static gboolean
_jxl_can_load(const guint8 *p_head, gsize u_len) {
return (detect_format(p_head, u_len) == GGAZE_FMT_JXL);
}
static GdkTexture *
_jxl_load(GFile *p_file, GCancellable *p_cancel, GError **p_err) {
(void)p_cancel;
gchar *c_buf = NULL;
gsize u_len = 0;
if (!g_file_load_contents(p_file, NULL, &c_buf, &u_len, NULL, p_err)) {
return (NULL);
}
JxlDecoder *p_dec = JxlDecoderCreate(NULL);
if (p_dec == NULL) {
g_free(c_buf);
g_set_error(p_err, G_IO_ERROR, G_IO_ERROR_FAILED,
"jxl: cannot create decoder");
return (NULL);
}
JxlDecoderSubscribeEvents(p_dec, JXL_DEC_BASIC_INFO | JXL_DEC_FULL_IMAGE);
JxlDecoderSetInput(p_dec, (const uint8_t *)c_buf, u_len);
JxlDecoderCloseInput(p_dec);
JxlBasicInfo st_info;
memset(&st_info, 0, sizeof(st_info));
uint8_t *p_pixels = NULL;
size_t u_w = 0, u_h = 0;
GdkTexture *p_tex = NULL;
for (;;) {
JxlDecoderStatus e_st = JxlDecoderProcessInput(p_dec);
if (e_st == JXL_DEC_ERROR) {
g_set_error(p_err, G_IO_ERROR, G_IO_ERROR_FAILED, "jxl: decode error");
break;
}
if (e_st == JXL_DEC_SUCCESS) {
/* Done — build the texture. */
if (p_pixels != NULL) {
GBytes *p_bytes = g_bytes_new_take(p_pixels, u_w * u_h * 4u);
p_pixels = NULL;
p_tex =
gdk_memory_texture_new((int)u_w, (int)u_h, GDK_MEMORY_R8G8B8A8,
p_bytes, (gsize)u_w * 4u);
g_bytes_unref(p_bytes);
}
break;
}
if (e_st == JXL_DEC_BASIC_INFO) {
JxlDecoderGetBasicInfo(p_dec, &st_info);
u_w = st_info.xsize;
u_h = st_info.ysize;
p_pixels = g_malloc(u_w * u_h * 4u);
JxlPixelFormat st_fmt = {4, JXL_TYPE_UINT8, JXL_NATIVE_ENDIAN, 0};
JxlDecoderSetImageOutBuffer(p_dec, &st_fmt, p_pixels, u_w * u_h * 4u);
} else if (e_st == JXL_DEC_FULL_IMAGE) {
/* pixels are now filled; continue to SUCCESS */
}
}
JxlDecoderDestroy(p_dec);
g_free(p_pixels);
g_free(c_buf);
return (p_tex);
}
const GgazeLoaderBackend jxl_backend = {
.can_load = _jxl_can_load,
.load = _jxl_load,
};
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