[FFmpeg-cvslog] avcodec/gif: fix issues with transparent crop

[Jacob Graff]

ffmpeg | branch: master | Jacob Graff <jacob at giphy.com> | Thu May  9 16:45:56 2019 -0400| [0158dd14a35ff88c4837d4b463e1f393040884c9] | committer: Paul B Mahol

avcodec/gif: fix issues with transparent crop

Resolves issues with some transparent gifs.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0158dd14a35ff88c4837d4b463e1f393040884c9
---

 libavcodec/gif.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libavcodec/gif.c b/libavcodec/gif.c
index 9f2f30d863..8c3bfdcc46 100644
--- a/libavcodec/gif.c
+++ b/libavcodec/gif.c
@@ -136,7 +136,7 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         while (*y_start < y_end) {
             int is_trans = 1;
             for (int i = 0; i < w; i++) {
-                if (buf[w * *y_start + i] != trans) {
+                if (buf[linesize * *y_start + i] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -148,10 +148,10 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         }
 
         // crop bottom
-        while (y_end < h) {
+        while (y_end > *y_start) {
             int is_trans = 1;
             for (int i = 0; i < w; i++) {
-                if (buf[w * y_end + i] != trans) {
+                if (buf[linesize * y_end + i] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -165,7 +165,7 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         while (*x_start < x_end) {
             int is_trans = 1;
             for (int i = *y_start; i < y_end; i++) {
-                if (buf[w * i + *x_start] != trans) {
+                if (buf[linesize * i + *x_start] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -176,10 +176,10 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         }
 
         // crop right
-        while (x_end < w) {
+        while (x_end > *x_start) {
             int is_trans = 1;
             for (int i = *y_start; i < y_end; i++) {
-                if (buf[w * i + x_end] != trans) {
+                if (buf[linesize * i + x_end] != trans) {
                     is_trans = 0;
                     break;
                 }