From 44b651eb5c84c3b4118d2892b25b35a750e113fb Mon Sep 17 00:00:00 2001
From: niksedk <nikse.dk@gmail.com>
Date: Fri, 20 Jan 2012 22:52:21 +0000
Subject: [PATCH] Improved left/right cropping for export images

git-svn-id: https://subtitleedit.googlecode.com/svn/trunk@940 99eadd0c-20b8-1223-b5c4-2a2b2df33de2
---
 src/Forms/ExportPngXml.cs |  5 +++-
 src/Logic/NikseBitmap.cs  | 60 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/src/Forms/ExportPngXml.cs b/src/Forms/ExportPngXml.cs
index 6223bc9cd..362e3d84c 100644
--- a/src/Forms/ExportPngXml.cs
+++ b/src/Forms/ExportPngXml.cs
@@ -474,7 +474,10 @@ namespace Nikse.SubtitleEdit.Forms
                 g.DrawPath(new Pen(parameter.BorderColor, parameter.BorderWidth), path);
             g.FillPath(new SolidBrush(parameter.SubtitleColor), path);
             g.Dispose();
-            return bmp;
+            NikseBitmap nbmp = new NikseBitmap(bmp);
+            nbmp.CropTransparentSides(5);
+            return nbmp.GetBitmap();
+            //return bmp;
         }
 
         private static string RemoveSubStationAlphaFormatting(string s)
diff --git a/src/Logic/NikseBitmap.cs b/src/Logic/NikseBitmap.cs
index a9c68ea7b..e16ae1767 100644
--- a/src/Logic/NikseBitmap.cs
+++ b/src/Logic/NikseBitmap.cs
@@ -357,6 +357,66 @@ namespace Nikse.SubtitleEdit.Logic
             return 0;
         }
 
+        public void CropTransparentSides(int maximumCropping)
+        {
+            int leftStart = 0;
+            bool done = false;
+            for (int x = 0; x < Width; x++)
+            {
+                for (int y = 0; y < Height; y++)
+                {
+                    Color c = GetPixel(x, y);
+                    if (c.A != 0)
+                    {
+                        done = true;
+                        leftStart = x;
+                        leftStart -= maximumCropping;
+                        if (leftStart < 0)
+                            leftStart = 0;
+                        break;
+                    }
+                    if (done)
+                        break;
+                }
+            }
+
+            int rightEnd = Width-1;
+            done = false;
+            for (int x = Width - 1; x >= 0; x--)
+            {
+                for (int y = 0; y < Height; y++)
+                {
+                    Color c = GetPixel(x, y);
+                    if (c.A != 0)
+                    {
+                        done = true;
+                        rightEnd = x;
+                        rightEnd += maximumCropping;
+                        if (rightEnd >= Width)
+                            rightEnd = Width-1;
+                        break;
+                    }
+                    if (done)
+                        break;
+                }
+            }
+
+            if (leftStart < 2 && rightEnd >= Width - 3)
+                return;
+
+            int newWidth = rightEnd - leftStart + 1;
+            var newBitmapData = new byte[newWidth * Height * 4];
+            int index = 0;
+            for (int y = 0; y < Height; y++)
+            {
+                int pixelAddress = (leftStart * 4) + (y * 4 * Width);
+                Buffer.BlockCopy(_bitmapData, pixelAddress, newBitmapData, index, 4 * newWidth);
+                index += 4 * newWidth;
+            }
+            Width = newWidth;
+            _bitmapData = newBitmapData;
+        }
+
         public void Fill(Color color)
         {
             byte[] buffer = new byte[4];