bitmap_packer: make manual use slightly more convenient

Apply the padding internally to each input bitmap, instead of requiring
this for the semi-public API.

Right now, everything still uses packer_pack_from_subbitmaps() to fill
the input bitmap sizes, but that's going to change with the following
commit. Since bitmap_packer.in is mutated during packing anyway, it's
more convenient to add the padding automatically.

Also, guarantee that every sub-bitmap has a padding border around it.
Don't let the padding overlap. Add padding even on the containing
borders.

This is simpler, doesn't cost much in memory usage, and is convenient
for one of the following commits.

1 files changed, 14 insertions, 12 deletions

diff --git a/video/out/bitmap_packer.c b/video/out/bitmap_packer.c
index 4896076422..4ea8b0b62a 100644
--- a/video/out/bitmap_packer.c
+++ b/video/out/bitmap_packer.c
@@ -46,10 +46,7 @@ void packer_reset(struct bitmap_packer *packer)
 void packer_get_bb(struct bitmap_packer *packer, struct pos out_bb[2])
 {
     out_bb[0] = (struct pos) {0};
-    out_bb[1] = (struct pos) {
-        FFMIN(packer->used_width + packer->padding, packer->w),
-        FFMIN(packer->used_height + packer->padding, packer->h),
-    };
+    out_bb[1] = (struct pos) {packer->used_width, packer->used_height};
 }
 
 #define HEIGHT_SORT_BITS 4
@@ -138,8 +135,12 @@ int packer_pack(struct bitmap_packer *packer)
     struct pos *in = packer->in;
     int xmax = 0, ymax = 0;
     for (int i = 0; i < packer->count; i++) {
-        if (in[i].x <= packer->padding || in[i].y <= packer->padding)
+        if (in[i].x <= 0 || in[i].y <= 0) {
             in[i] = (struct pos){0, 0};
+        } else {
+            in[i].x += packer->padding * 2;
+            in[i].y += packer->padding * 2;
+        }
         if (in[i].x < 0 || in [i].x > 65535 || in[i].y < 0 || in[i].y > 65535) {
             fprintf(stderr, "Invalid OSD / subtitle bitmap size\n");
             abort();
@@ -147,8 +148,6 @@ int packer_pack(struct bitmap_packer *packer)
         xmax = FFMAX(xmax, in[i].x);
         ymax = FFMAX(ymax, in[i].y);
     }
-    xmax = FFMAX(0, xmax - packer->padding);
-    ymax = FFMAX(0, ymax - packer->padding);
     if (xmax > packer->w)
         packer->w = 1 << (av_log2(xmax - 1) + 1);
     if (ymax > packer->h)
@@ -156,15 +155,19 @@ int packer_pack(struct bitmap_packer *packer)
     while (1) {
         int used_width = 0;
         int y = pack_rectangles(in, packer->result, packer->count,
-                                packer->w + packer->padding,
-                                packer->h + packer->padding,
+                                packer->w, packer->h,
                                 packer->scratch, &used_width);
         if (y >= 0) {
-            // No padding at edges
             packer->used_width = FFMIN(used_width, packer->w);
             packer->used_height = FFMIN(y, packer->h);
             assert(packer->w == 0 || IS_POWER_OF_2(packer->w));
             assert(packer->h == 0 || IS_POWER_OF_2(packer->h));
+            if (packer->padding) {
+                for (int i = 0; i < packer->count; i++) {
+                    packer->result[i].x += packer->padding;
+                    packer->result[i].y += packer->padding;
+                }
+            }
             return packer->w != w_orig || packer->h != h_orig;
         }
         if (packer->w <= packer->h && packer->w != packer->w_max)
@@ -201,9 +204,8 @@ int packer_pack_from_subbitmaps(struct bitmap_packer *packer,
     if (b->format == SUBBITMAP_EMPTY)
         return 0;
     packer_set_size(packer, b->num_parts);
-    int a = packer->padding;
     for (int i = 0; i < b->num_parts; i++)
-        packer->in[i] = (struct pos){b->parts[i].w + a, b->parts[i].h + a};
+        packer->in[i] = (struct pos){b->parts[i].w, b->parts[i].h};
     return packer_pack(packer);
 }