From 20fbe78290c5e9bb8ae9a5d58f22137b69c7b513 Mon Sep 17 00:00:00 2001
From: Ville Sundell <development@solarius.fi>
Date: Fri, 23 Jan 2026 22:24:36 +0200
Subject: [PATCH] Add gd_copy_frame_data()

The gd_render_frame() copies the pixel-ready picture to the
destination buffer, by converting the palette entries into three-byte
colored pixels.

However, this is not always desired. For example in applications which
need to preserve the pixel - palette relationship for further
processing.

Hence the new gd_copy_frame_data() function, which copies only the
raw data (pixels represent palette indexes, not colors per se).
---
 gifdec.c | 7 +++++++
 gifdec.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/gifdec.c b/gifdec.c
index 83c2d0f..9a97923 100644
--- a/gifdec.c
+++ b/gifdec.c
@@ -509,6 +509,13 @@ gd_render_frame(gd_GIF *gif, uint8_t *buffer)
     render_frame_rect(gif, buffer);
 }
 
+/* Extract the raw frame data (pixels represent palette indexes) */
+void
+gd_copy_frame_data(gd_GIF *gif, uint8_t *buffer)
+{
+    memcpy(buffer, gif->frame, gif->width * gif->height);
+}
+
 int
 gd_is_bgcolor(gd_GIF *gif, uint8_t color[3])
 {
diff --git a/gifdec.h b/gifdec.h
index 2bbc9f5..92dea3b 100644
--- a/gifdec.h
+++ b/gifdec.h
@@ -45,6 +45,7 @@ typedef struct gd_GIF {
 gd_GIF *gd_open_gif(const char *fname);
 int gd_get_frame(gd_GIF *gif);
 void gd_render_frame(gd_GIF *gif, uint8_t *buffer);
+void gd_copy_frame_data(gd_GIF *gif, uint8_t *buffer);
 int gd_is_bgcolor(gd_GIF *gif, uint8_t color[3]);
 void gd_rewind(gd_GIF *gif);
 void gd_close_gif(gd_GIF *gif);