drawutils: new API.

This new API stores useful data in a dedicated structure
and has clearly delimited init functions.

Hopefully, uses of the old API can be replaced quickly.

libavfilter/Makefile

@@ -169,6 +169,6 @@ OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/pullup.o
 
 DIRS = x86 libmpcodecs
 
-TESTPROGS = formats
+TESTPROGS = drawutils formats
 
 TOOLS = graph2dot lavfi-showfiltfmts

libavfilter/drawutils.c

@@ -26,11 +26,15 @@ enum { RED = 0, GREEN, BLUE, ALPHA };
 int ff_fill_rgba_map(uint8_t *rgba_map, enum PixelFormat pix_fmt)
 {
     switch (pix_fmt) {
+    case PIX_FMT_0RGB:
     case PIX_FMT_ARGB:  rgba_map[ALPHA] = 0; rgba_map[RED  ] = 1; rgba_map[GREEN] = 2; rgba_map[BLUE ] = 3; break;
+    case PIX_FMT_0BGR:
     case PIX_FMT_ABGR:  rgba_map[ALPHA] = 0; rgba_map[BLUE ] = 1; rgba_map[GREEN] = 2; rgba_map[RED  ] = 3; break;
+    case PIX_FMT_RGB0:
     case PIX_FMT_RGBA:
     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_BGR0:
     case PIX_FMT_BGR24: rgba_map[BLUE ] = 0; rgba_map[GREEN] = 1; rgba_map[RED  ] = 2; rgba_map[ALPHA] = 3; break;
     default:                    /* unsupported */
         return AVERROR(EINVAL);
@@ -120,3 +124,189 @@ void ff_copy_rectangle(uint8_t *dst[4], int dst_linesize[4],
         }
     }
 }
+
+int ff_draw_init(FFDrawContext *draw, enum PixelFormat format, unsigned flags)
+{
+    const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[format];
+    const AVComponentDescriptor *c;
+    unsigned i, nb_planes = 0;
+    int pixelstep[MAX_PLANES] = { 0 };
+
+    if (desc->flags & ~(PIX_FMT_PLANAR | PIX_FMT_RGB))
+        return AVERROR(ENOSYS);
+    for (i = 0; i < desc->nb_components; i++) {
+        c = &desc->comp[i];
+        /* for now, only 8-bits formats */
+        if (c->depth_minus1 != 8 - 1)
+            return AVERROR(ENOSYS);
+        if (c->plane >= MAX_PLANES)
+            return AVERROR(ENOSYS);
+        /* strange interleaving */
+        if (pixelstep[c->plane] != 0 &&
+            pixelstep[c->plane] != c->step_minus1 + 1)
+            return AVERROR(ENOSYS);
+        pixelstep[c->plane] = c->step_minus1 + 1;
+        nb_planes = FFMAX(nb_planes, c->plane + 1);
+    }
+    if ((desc->log2_chroma_w || desc->log2_chroma_h) && nb_planes < 3)
+        return AVERROR(ENOSYS); /* exclude NV12 and NV21 */
+    memset(draw, 0, sizeof(*draw));
+    draw->desc      = desc;
+    draw->format    = format;
+    draw->nb_planes = nb_planes;
+    memcpy(draw->pixelstep, pixelstep, sizeof(draw->pixelstep));
+    if (nb_planes >= 3 && !(desc->flags & PIX_FMT_RGB)) {
+        draw->hsub[1] = draw->hsub[2] = draw->hsub_max = desc->log2_chroma_w;
+        draw->vsub[1] = draw->vsub[2] = draw->vsub_max = desc->log2_chroma_h;
+    }
+    return 0;
+}
+
+void ff_draw_color(FFDrawContext *draw, FFDrawColor *color, uint8_t rgba[4])
+{
+    unsigned i;
+    uint8_t rgba_map[4];
+
+    if ((draw->desc->flags & PIX_FMT_RGB) && draw->nb_planes == 1 &&
+        ff_fill_rgba_map(rgba_map, draw->format) >= 0) {
+        for (i = 0; i < 4; i++)
+            color->comp[0].u8[rgba_map[i]] = rgba[i];
+    } else if (draw->nb_planes == 3 || draw->nb_planes == 4) {
+        /* assume YUV */
+        color->comp[0].u8[0] = RGB_TO_Y_CCIR(rgba[0], rgba[1], rgba[2]);
+        color->comp[1].u8[0] = RGB_TO_U_CCIR(rgba[0], rgba[1], rgba[2], 0);
+        color->comp[2].u8[0] = RGB_TO_V_CCIR(rgba[0], rgba[1], rgba[2], 0);
+        color->comp[3].u8[0] = rgba[3];
+    } else if (draw->format == PIX_FMT_GRAY8 || draw->format == PIX_FMT_GRAY8A) {
+        color->comp[0].u8[0] = RGB_TO_Y_CCIR(rgba[0], rgba[1], rgba[2]);
+        color->comp[1].u8[0] = rgba[3];
+    } else {
+        av_log(NULL, AV_LOG_WARNING,
+               "Color conversion not implemented for %s\n", draw->desc->name);
+        memset(color, 128, sizeof(*color));
+    }
+}
+
+static uint8_t *pointer_at(FFDrawContext *draw, uint8_t *data[], int linesize[],
+                           int plane, int x, int y)
+{
+    return data[plane] +
+           (y >> draw->vsub[plane]) * linesize[plane] +
+           (x >> draw->hsub[plane]) * draw->pixelstep[plane];
+}
+
+void ff_copy_rectangle2(FFDrawContext *draw,
+                        uint8_t *dst[], int dst_linesize[],
+                        uint8_t *src[], int src_linesize[],
+                        int dst_x, int dst_y, int src_x, int src_y,
+                        int w, int h)
+{
+    int plane, y, wp, hp;
+    uint8_t *p, *q;
+
+    for (plane = 0; plane < draw->nb_planes; plane++) {
+        p = pointer_at(draw, src, src_linesize, plane, src_x, src_y);
+        q = pointer_at(draw, dst, dst_linesize, plane, dst_x, dst_y);
+        wp = (w >> draw->hsub[plane]) * draw->pixelstep[plane];
+        hp = (h >> draw->vsub[plane]);
+        for (y = 0; y < hp; y++) {
+            memcpy(q, p, wp);
+            p += src_linesize[plane];
+            q += dst_linesize[plane];
+        }
+    }
+}
+
+void ff_fill_rectangle(FFDrawContext *draw, FFDrawColor *color,
+                       uint8_t *dst[], int dst_linesize[],
+                       int dst_x, int dst_y, int w, int h)
+{
+    int plane, x, y, wp, hp;
+    uint8_t *p0, *p;
+
+    for (plane = 0; plane < draw->nb_planes; plane++) {
+        p0 = pointer_at(draw, dst, dst_linesize, plane, dst_x, dst_y);
+        wp = (w >> draw->hsub[plane]);
+        hp = (h >> draw->vsub[plane]);
+        if (!hp)
+            return;
+        p = p0;
+        /* copy first line from color */
+        for (x = 0; x < wp; x++) {
+            memcpy(p, color->comp[plane].u8, draw->pixelstep[plane]);
+            p += draw->pixelstep[plane];
+        }
+        wp *= draw->pixelstep[plane];
+        /* copy next lines from first line */
+        p = p0 + dst_linesize[plane];
+        for (y = 1; y < hp; y++) {
+            memcpy(p, p0, wp);
+            p += dst_linesize[plane];
+        }
+    }
+}
+
+int ff_draw_round_to_sub(FFDrawContext *draw, int sub_dir, int round_dir,
+                         int value)
+{
+    unsigned shift = sub_dir ? draw->vsub_max : draw->hsub_max;
+
+    if (!shift)
+        return value;
+    if (round_dir >= 0)
+        value += round_dir ? (1 << shift) - 1 : 1 << (shift - 1);
+    return (value >> shift) << shift;
+}
+
+AVFilterFormats *ff_draw_supported_pixel_formats(unsigned flags)
+{
+    enum PixelFormat i, pix_fmts[PIX_FMT_NB + 1];
+    unsigned n = 0;
+    FFDrawContext draw;
+
+    for (i = 0; i < PIX_FMT_NB; i++)
+        if (ff_draw_init(&draw, i, flags) >= 0)
+            pix_fmts[n++] = i;
+    pix_fmts[n++] = PIX_FMT_NONE;
+    return avfilter_make_format_list(pix_fmts);
+}
+
+#ifdef TEST
+
+#undef printf
+
+int main(void)
+{
+    enum PixelFormat f;
+    const AVPixFmtDescriptor *desc;
+    FFDrawContext draw;
+    FFDrawColor color;
+    int r, i;
+
+    for (f = 0; f < PIX_FMT_NB; f++) {
+        desc = &av_pix_fmt_descriptors[f];
+        if (!desc->name)
+            continue;
+        printf("Testing %s...%*s", desc->name,
+               (int)(16 - strlen(desc->name)), "");
+        r = ff_draw_init(&draw, f, 0);
+        if (r < 0) {
+            char buf[128];
+            av_strerror(r, buf, sizeof(buf));
+            printf("no: %s\n", buf);
+            continue;
+        }
+        ff_draw_color(&draw, &color, (uint8_t[]) { 1, 0, 0, 1 });
+        for (i = 0; i < sizeof(color); i++)
+            if (((uint8_t *)&color)[i] != 128)
+                break;
+        if (i == sizeof(color)) {
+            printf("fallback color\n");
+            continue;
+        }
+        printf("ok\n");
+    }
+    return 0;
+}
+
+#endif

libavfilter/drawutils.h

@@ -25,6 +25,7 @@
  */
 
 #include <stdint.h>
+#include "avfilter.h"
 #include "libavutil/pixfmt.h"
 
 int ff_fill_rgba_map(uint8_t *rgba_map, enum PixelFormat pix_fmt);
@@ -42,4 +43,80 @@ void ff_copy_rectangle(uint8_t *dst[4], int dst_linesize[4],
                        uint8_t *src[4], int src_linesize[4], int pixelstep[4],
                        int hsub, int vsub, int x, int y, int y2, int w, int h);
 
+#define MAX_PLANES 4
+
+typedef struct FFDrawContext {
+    const struct AVPixFmtDescriptor *desc;
+    enum PixelFormat format;
+    unsigned nb_planes;
+    int pixelstep[MAX_PLANES]; /*< offset between pixels */
+    uint8_t hsub[MAX_PLANES];  /*< horizontal subsamling */
+    uint8_t vsub[MAX_PLANES];  /*< vertical subsamling */
+    uint8_t hsub_max;
+    uint8_t vsub_max;
+} FFDrawContext;
+
+typedef struct FFDrawColor {
+    union {
+        uint32_t u32;
+        uint16_t u16;
+        uint8_t  u8[4];
+    } comp[MAX_PLANES];
+} FFDrawColor;
+
+/**
+ * Init a draw context.
+ *
+ * Only a limited number of pixel formats are supported, if format is not
+ * supported the function will return an error.
+ * No flags currently defined.
+ * @return  0 for success, < 0 for error
+ */
+int ff_draw_init(FFDrawContext *draw, enum PixelFormat format, unsigned flags);
+
+/**
+ * Prepare a color.
+ */
+void ff_draw_color(FFDrawContext *draw, FFDrawColor *color, uint8_t rgba[4]);
+
+/**
+ * Copy a rectangle from an image to another.
+ *
+ * The coordinates must be as even as the subsampling requires.
+ */
+void ff_copy_rectangle2(FFDrawContext *draw,
+                        uint8_t *dst[], int dst_linesize[],
+                        uint8_t *src[], int src_linesize[],
+                        int dst_x, int dst_y, int src_x, int src_y,
+                        int w, int h);
+
+/**
+ * Fill a rectangle with an uniform color.
+ *
+ * The coordinates must be as even as the subsampling requires.
+ * The color needs to be inited with ff_draw_color.
+ */
+void ff_fill_rectangle(FFDrawContext *draw, FFDrawColor *color,
+                       uint8_t *dst[], int dst_linesize[],
+                       int dst_x, int dst_y, int w, int h);
+
+/**
+ * Round a dimension according to subsampling.
+ *
+ * @param draw       draw context
+ * @param sub_dir    0 for horizontal, 1 for vertical
+ * @param round_dir  0 nearest, -1 round down, +1 round up
+ * @param value      value to round
+ * @return  the rounded value
+ */
+int ff_draw_round_to_sub(FFDrawContext *draw, int sub_dir, int round_dir,
+                         int value);
+
+/**
+ * Return the list of pixel formats supported by the draw functions.
+ *
+ * The flags are the same as ff_draw_init, i.e., none currently.
+ */
+AVFilterFormats *ff_draw_supported_pixel_formats(unsigned flags);
+
 #endif /* AVFILTER_DRAWUTILS_H */