From: Robert Roebling <robert@roebling.de>
Date: Sun, 29 Jan 2006 15:44:21 +0000 (+0000)
Subject:   Fix rawbitmap sample to clear bitmap first.
X-Git-Url: https://git.saurik.com/wxWidgets.git/commitdiff_plain/6e5551ad85f73b14b02f42a26ab5609ab4b8d468

  Fix rawbitmap sample to clear bitmap first.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@37210 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---

diff --git a/samples/image/image.cpp b/samples/image/image.cpp
index 04e04cd670..317fe045fb 100644
--- a/samples/image/image.cpp
+++ b/samples/image/image.cpp
@@ -304,8 +304,33 @@ public:
         // another possibility: wxNativePixelData (don't forget to remove code
         // setting alpha in the loop below then)
         typedef wxAlphaPixelData Data;
+        // typedef wxNativePixelData Data;
+        
+        // First, clear the whole bitmap by making it alpha
+        {
+            Data data( m_bitmap, wxPoint(0,0), wxSize(SIZE, SIZE) );
+            if ( !data )
+            {
+                wxLogError(_T("Failed to gain raw access to bitmap data"));
+                return;
+            }
+            data.UseAlpha();
+            Data::Iterator p(data);
+            for ( int y = 0; y < SIZE; ++y )
+            {
+                Data::Iterator rowStart = p;
+                for ( int x = 0; x < SIZE; ++x )
+                {
+                    p.Alpha() = 0;
+                    ++p; // same as p.OffsetX(1)
+                }
+                p = rowStart;
+                p.OffsetY(data, 1);
+            }
+        }
 
-        Data data(m_bitmap, wxPoint(BORDER, BORDER), wxSize(REAL_SIZE, REAL_SIZE));
+        // Then, draw colourful alpha-blended stripes
+        Data data(m_bitmap, wxPoint(BORDER, BORDER) , wxSize(REAL_SIZE, REAL_SIZE));
         if ( !data )
         {
             wxLogError(_T("Failed to gain raw access to bitmap data"));