From 0905746c0cf661c0f598a859a59d9146ac512926 Mon Sep 17 00:00:00 2001
From: Vineeth TM <vineeth.tm@samsung.com>
Date: Tue, 2 Jun 2015 10:21:42 +0900
Subject: [PATCH] simplevideomark: fix display of videomark partially or fully
 outside video

In case of the videomark being partially or fully outside, an error was being
thrown saying the mark width is more than video width. And when the width,
offset properties are set to maximum it resulted in crash. Instead of throwing
an error, add logic to detect the mark in case of partial visibility or don't
show the mark when it is outside.

https://bugzilla.gnome.org/show_bug.cgi?id=743908
---
 gst/videosignal/gstsimplevideomark.c | 88 ++++++++++++++++++++++------
 1 file changed, 70 insertions(+), 18 deletions(-)

diff --git a/gst/videosignal/gstsimplevideomark.c b/gst/videosignal/gstsimplevideomark.c
index d62af9b8d5..a0fb1fe320 100644
--- a/gst/videosignal/gstsimplevideomark.c
+++ b/gst/videosignal/gstsimplevideomark.c
@@ -331,14 +331,26 @@ gst_video_mark_draw_box (GstSimpleVideoMark * simplevideomark, guint8 * data,
   }
 }
 
+static gint
+calculate_pw (gint pw, gint x, gint width)
+{
+  if (x < 0)
+    pw += x;
+  else if ((x + pw) > width)
+    pw = width - x;
+
+  return pw;
+}
+
 static GstFlowReturn
 gst_video_mark_yuv (GstSimpleVideoMark * simplevideomark, GstVideoFrame * frame)
 {
   gint i, pw, ph, row_stride, pixel_stride;
-  gint width, height, req_width, req_height;
+  gint width, height, offset_calc, x, y;
   guint8 *d;
   guint64 pattern_shift;
   guint8 color;
+  gint total_pattern;
 
   width = frame->info.width;
   height = frame->info.height;
@@ -348,36 +360,63 @@ gst_video_mark_yuv (GstSimpleVideoMark * simplevideomark, GstVideoFrame * frame)
   row_stride = GST_VIDEO_FRAME_COMP_STRIDE (frame, 0);
   pixel_stride = GST_VIDEO_FRAME_COMP_PSTRIDE (frame, 0);
 
-  req_width =
-      (simplevideomark->pattern_count +
-      simplevideomark->pattern_data_count) * pw + simplevideomark->left_offset;
-  req_height = simplevideomark->bottom_offset + ph;
-  if (req_width > width || req_height > height) {
-    GST_ELEMENT_ERROR (simplevideomark, STREAM, WRONG_TYPE, (NULL),
-        ("simplevideomark pattern doesn't fit video, need at least %ix%i (stream has %ix%i)",
-            req_width, req_height, width, height));
-    return GST_FLOW_ERROR;
-  }
-
   d = GST_VIDEO_FRAME_COMP_DATA (frame, 0);
-  /* move to start of bottom left */
-  d += row_stride * (height - ph - simplevideomark->bottom_offset) +
+  offset_calc =
+      row_stride * (height - ph - simplevideomark->bottom_offset) +
       pixel_stride * simplevideomark->left_offset;
+  x = simplevideomark->left_offset;
+  y = height - ph - simplevideomark->bottom_offset;
+
+  total_pattern =
+      simplevideomark->pattern_count + simplevideomark->pattern_data_count;
+  /* If x and y offset values are outside the video, no need to draw */
+  if ((x + (pw * total_pattern)) < 0 || x > width || (y + height) < 0
+      || y > height)
+    return GST_FLOW_OK;
+
+  /* Offset calculation less than 0, then reset to 0 */
+  if (offset_calc < 0)
+    offset_calc = 0;
+  /* Y position of mark is negative or pattern exceeds the video height,
+     then recalculate pattern height for partial display */
+  if (y < 0)
+    ph += y;
+  else if ((y + ph) > height)
+    ph = height - y;
+  /* If pattern height is less than 0, need not draw anything */
+  if (ph < 0)
+    return GST_FLOW_OK;
+
+  /* move to start of bottom left */
+  d += offset_calc;
 
   /* draw the bottom left pixels */
   for (i = 0; i < simplevideomark->pattern_count; i++) {
+    gint draw_pw;
+
     if (i & 1)
       /* odd pixels must be white */
       color = 255;
     else
       color = 0;
 
+    /* X position of mark is negative or pattern exceeds the video width,
+       then recalculate pattern width for partial display */
+    draw_pw = calculate_pw (pw, x, width);
+    /* If pattern width is less than 0, continue with the next pattern */
+    if (draw_pw < 0)
+      continue;
+
     /* draw box of width * height */
-    gst_video_mark_draw_box (simplevideomark, d, pw, ph, row_stride,
+    gst_video_mark_draw_box (simplevideomark, d, draw_pw, ph, row_stride,
         pixel_stride, color);
 
     /* move to i-th pattern */
-    d += pixel_stride * pw;
+    d += pixel_stride * draw_pw;
+    x += draw_pw;
+
+    if ((x + (pw * (total_pattern - i - 1))) < 0 || x >= width)
+      return GST_FLOW_OK;
   }
 
   pattern_shift =
@@ -385,18 +424,31 @@ gst_video_mark_yuv (GstSimpleVideoMark * simplevideomark, GstVideoFrame * frame)
 
   /* get the data of the pattern */
   for (i = 0; i < simplevideomark->pattern_data_count; i++) {
+    gint draw_pw;
     if (simplevideomark->pattern_data & pattern_shift)
       color = 255;
     else
       color = 0;
 
-    gst_video_mark_draw_box (simplevideomark, d, pw, ph, row_stride,
+    /* X position of mark is negative or pattern exceeds the video width,
+       then recalculate pattern width for partial display */
+    draw_pw = calculate_pw (pw, x, width);
+    /* If pattern width is less than 0, continue with the next pattern */
+    if (draw_pw < 0)
+      continue;
+
+    gst_video_mark_draw_box (simplevideomark, d, draw_pw, ph, row_stride,
         pixel_stride, color);
 
     pattern_shift >>= 1;
 
     /* move to i-th pattern data */
-    d += pixel_stride * pw;
+    d += pixel_stride * draw_pw;
+    x += draw_pw;
+
+    if ((x + (pw * (simplevideomark->pattern_data_count - i - 1))) < 0
+        || x >= width)
+      return GST_FLOW_OK;
   }
 
   return GST_FLOW_OK;
-- 
2.34.1