lavfi: add internal function ff_fill_rgba_map()

libavfilter/drawutils.c

@@ -23,16 +23,8 @@
 
 enum { RED = 0, GREEN, BLUE, ALPHA };
 
-int ff_fill_line_with_color(uint8_t *line[4], int pixel_step[4], int w, uint8_t dst_color[4],
-                            enum PixelFormat pix_fmt, uint8_t rgba_color[4],
-                            int *is_packed_rgba, uint8_t rgba_map_ptr[4])
+int ff_fill_rgba_map(uint8_t *rgba_map, enum PixelFormat pix_fmt)
 {
-    uint8_t rgba_map[4] = {0};
-    int i;
-    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[pix_fmt];
-    int hsub = pix_desc->log2_chroma_w;
-
-    *is_packed_rgba = 1;
     switch (pix_fmt) {
     case PIX_FMT_ARGB:  rgba_map[ALPHA] = 0; rgba_map[RED  ] = 1; rgba_map[GREEN] = 2; rgba_map[BLUE ] = 3; break;
     case PIX_FMT_ABGR:  rgba_map[ALPHA] = 0; rgba_map[BLUE ] = 1; rgba_map[GREEN] = 2; rgba_map[RED  ] = 3; break;
@@ -40,9 +32,22 @@ int ff_fill_line_with_color(uint8_t *line[4], int pixel_step[4], int w, uint8_t
     case PIX_FMT_RGB24: rgba_map[RED  ] = 0; rgba_map[GREEN] = 1; rgba_map[BLUE ] = 2; rgba_map[ALPHA] = 3; break;
     case PIX_FMT_BGRA:
     case PIX_FMT_BGR24: rgba_map[BLUE ] = 0; rgba_map[GREEN] = 1; rgba_map[RED  ] = 2; rgba_map[ALPHA] = 3; break;
-    default:
-        *is_packed_rgba = 0;
+    default:                    /* unsupported */
+        return AVERROR(EINVAL);
     }
+    return 0;
+}
+
+int ff_fill_line_with_color(uint8_t *line[4], int pixel_step[4], int w, uint8_t dst_color[4],
+                            enum PixelFormat pix_fmt, uint8_t rgba_color[4],
+                            int *is_packed_rgba, uint8_t rgba_map_ptr[4])
+{
+    uint8_t rgba_map[4] = {0};
+    int i;
+    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[pix_fmt];
+    int hsub = pix_desc->log2_chroma_w;
+
+    *is_packed_rgba = ff_fill_rgba_map(rgba_map, pix_fmt) >= 0;
 
     if (*is_packed_rgba) {
         pixel_step[0] = (av_get_bits_per_pixel(pix_desc))>>3;

libavfilter/drawutils.h

@@ -27,6 +27,8 @@
 #include <stdint.h>
 #include "libavutil/pixfmt.h"
 
+int ff_fill_rgba_map(uint8_t *rgba_map, enum PixelFormat pix_fmt);
+
 int ff_fill_line_with_color(uint8_t *line[4], int pixel_step[4], int w,
                             uint8_t dst_color[4],
                             enum PixelFormat pix_fmt, uint8_t rgba_color[4],