Document the internal alpha channel format better, and fixes for 32bit alpha bitmaps.

For images, rows need to be even (this is not true for anti-aliased font files).
Fix stride and size calculation. This makes images that have odd pixel rows display properly and fixes buffer overflows.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30966 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 2 insertions, 2 deletions

diff --git a/apps/recorder/resize.c b/apps/recorder/resize.c
index a68a5f2e9f..dd1f3edf88 100644
--- a/apps/recorder/resize.c
+++ b/apps/recorder/resize.c
@@ -775,7 +775,7 @@ static void output_row_32_native(uint32_t row, void * row_in,
                 if (ctx->bm->alpha_offset > 0)
                     bm_alpha = ctx->bm->data + ctx->bm->alpha_offset;
                 if (bm_alpha)
-                    bm_alpha += ctx->bm->width*row/2;
+                    bm_alpha += ALIGN_UP(ctx->bm->width, 2)*row/2;
 
                 for (col = 0; col < ctx->bm->width; col++) {
                     if (ctx->dither)
@@ -791,7 +791,7 @@ static void output_row_32_native(uint32_t row, void * row_in,
                     dest += STRIDE_MAIN(1, ctx->bm->height);
                     if (bm_alpha) {
                         /* pack alpha channel for 2 pixels into 1 byte */
-                        unsigned alpha = 255-SC_OUT(q0.a, ctx);
+                        unsigned alpha = SC_OUT(q0.a, ctx);
                         if (col%2)
                             *bm_alpha++ |= alpha&0xf0;
                         else