Changeset 856 for branches/eraser6/Eraser/AboutForm.cs

Timestamp:

1/5/2009 10:47:44 AM (3 years ago)

Author:

lowjoel

Message:

Implemented a slightly (performance increase by 200%) faster about box drawing algorithm. Fixes #136.

File:

• branches/eraser6/Eraser/AboutForm.cs (modified) (2 diffs)

branches/eraser6/Eraser/AboutForm.cs

@@ -192 +192 @@
         }
 
+        private void AboutForm_Paint(object sender, PaintEventArgs e)
+        {
+            DrawComposite(e.Graphics);
+        }
+
         private void AboutForm_MouseMove(object sender, MouseEventArgs e)
         {
@@ -217 +222 @@
                 AboutTextScrollTop -= 1;
 
-            DrawComposite();
-        }
-
-        private void DrawComposite()
+            using (Graphics g = CreateGraphics())
+                DrawComposite(g);
+        }
+
+        private void DrawComposite(Graphics g)
         {
             if (DoubleBufferBitmap == null)
                 DoubleBufferBitmap = new Bitmap(ClientSize.Width, ClientSize.Height);
-            using (Graphics g = Graphics.FromImage(DoubleBufferBitmap))
+            using (Graphics bg = Graphics.FromImage(DoubleBufferBitmap))
             {
                 //Draw the parent image with a fading out effect
+                if (ParentOpacity > 128)
+                    bg.Clip = new Region(AboutTextRect);
+
                 Brush brush = new SolidBrush(Color.FromArgb(ParentOpacity, 0, 0, 0));
-                g.DrawImageUnscaled(ParentBitmap, 0, 0);
-                g.FillRectangle(brush, ClientRectangle);
+                bg.DrawImageUnscaled(ParentBitmap, 0, 0);
+                bg.FillRectangle(brush, ClientRectangle);
 
                 //Then draw the About bitmap (which we cached in the constructor)
-                g.DrawImageUnscaled(AboutBitmap, AboutBitmapPos);
+                bg.DrawImageUnscaled(AboutBitmap, AboutBitmapPos);
 
                 //And the scrolling text
-                g.Clip = new Region(AboutTextRect);
-                g.DrawImageUnscaled(AboutTextBitmap, AboutTextRect.Left,
+                bg.Clip = new Region(AboutTextRect);
+                bg.DrawImageUnscaled(AboutTextBitmap, AboutTextRect.Left,
                     AboutTextRect.Top + AboutTextScrollTop);
-                g.ResetClip();
-            }
-
-            using (Graphics g = CreateGraphics())
-                g.DrawImageUnscaled(DoubleBufferBitmap, 0, 0);
+                bg.ResetClip();
+            }
+
+            if (ParentOpacity > 128)
+                if (g.Clip != null)
+                    g.Clip.Complement(new Region(AboutTextRect));
+                else
+                    g.Clip = new Region(AboutTextRect);
+            g.DrawImageUnscaled(DoubleBufferBitmap, 0, 0);
         }
     }