Fix use of iclip and movevc with larger values causing content invisible

sorayuki · May 21, 2022 · 79f476b · 79f476b
1 parent 4364568
commit 79f476b
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Showing 3 changed files with 5 additions and 2 deletions.
diff --git a/src/subtitles/RTS.cpp b/src/subtitles/RTS.cpp
@@ -3756,6 +3756,7 @@ STDMETHODIMP CRenderedTextSubtitle::Render(SubPicDesc& spd, REFERENCE_TIME rt, d
                 }
                 else mod_vc.pos = vcpos2;
                 mod_vc.enable = true;
+                mod_vc.isInverse = s->m_pClipper ? s->m_pClipper->m_inverse : false;
             }
 #endif
             break;

diff --git a/src/subtitles/Rasterizer.cpp b/src/subtitles/Rasterizer.cpp
@@ -2162,6 +2162,7 @@ void MOD_MOVEVC::clear()
     curpos = CPoint(0, 0);
     hfull = 0;
     alphamask = NULL;
+    isInverse = false;
 }
 
 byte MOD_MOVEVC::GetAlphaValue(int wx, int wy)
@@ -2178,9 +2179,9 @@ byte MOD_MOVEVC::GetAlphaValue(int wx, int wy)
 
     //check if the point is in canvas, in case of crash
     if (xInCanvas < 0 || xInCanvas >= spd.cx)
-        alpham = 0;
+        alpham = isInverse ? 0x40 : 0; // assume content outside canvas is visible when using iclip. mask is 6 bit
     else if (yInCanvas < 0 || yInCanvas >= spd.cy)
-        alpham = 0;
+        alpham = isInverse ? 0x40 : 0;
     else
     {
         if ((wx - pos.x) < -curpos.x + 1) alpham = 0;

diff --git a/src/subtitles/Rasterizer.h b/src/subtitles/Rasterizer.h
@@ -41,6 +41,7 @@ class MOD_MOVEVC
     CPoint curpos;  // output origin point
     int hfull;		// full height
     byte* alphamask;
+    bool isInverse;
 
     MOD_MOVEVC();