No changes, just refactor wxCairoBitmapData ctor.

Extract the code for buffer and surface creation into separate helper
functions so that they could be reused by other constructors (to be added in
the next commits).

Also use cairo_format_stride_for_width(), if available, to compute the stride
for the surfaces we create instead of hard coding 4*width.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69352 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/generic/graphicc.cpp b/src/generic/graphicc.cpp
index a6bee21072bd39d3d4c09dd3369f90e131555c65..0f14fa284b99b87599c20ac3bb7065a6668b624e 100644 (file)
--- a/src/generic/graphicc.cpp
+++ b/src/generic/graphicc.cpp
@@ -318,6 +318,16 @@ public:
     virtual cairo_pattern_t* GetCairoPattern() { return m_pattern; }
     virtual wxSize GetSize() { return wxSize(m_width, m_height); }
 private :
+    // Allocate m_buffer for the bitmap of the given size in the given format.
+    //
+    // Returns the stride used for the buffer.
+    int InitBuffer(int width, int height, cairo_format_t format);
+
+    // Really create the surface using the buffer (which was supposed to be
+    // filled since InitBuffer() call).
+    void InitSurface(cairo_format_t format, int stride);
+
+
     cairo_surface_t* m_surface;
     cairo_pattern_t* m_pattern;
     int m_width;
@@ -1069,8 +1079,49 @@ void * wxCairoMatrixData::GetNativeMatrix() const
     return (void*) &m_matrix;
 }
 
+// ----------------------------------------------------------------------------
 // wxCairoBitmap implementation
-//-----------------------------------------------------------------------------
+// ----------------------------------------------------------------------------
+
+int wxCairoBitmapData::InitBuffer(int width, int height, cairo_format_t format)
+{
+    wxUnusedVar(format); // Only really unused with Cairo < 1.6.
+
+    // Determine the stride: use cairo_format_stride_for_width() if available
+    // but fall back to 4*width for the earlier versions as this is what that
+    // function always returns, even in latest Cairo, anyhow.
+    int stride;
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 6, 0)
+    if ( cairo_version() >= CAIRO_VERSION_ENCODE(1, 6, 0) )
+    {
+        stride = cairo_format_stride_for_width(format, width);
+
+        // All our code would totally break if stride were not a multiple of 4
+        // so ensure this is the case.
+        if ( stride % 4 )
+        {
+            wxFAIL_MSG("Unexpected Cairo image surface stride.");
+
+            stride += 4 - stride % 4;
+        }
+    }
+    else
+#endif
+        stride = 4*width;
+
+    m_width = width;
+    m_height = height;
+    m_buffer = new unsigned char[height*stride];
+
+    return stride;
+}
+
+void wxCairoBitmapData::InitSurface(cairo_format_t format, int stride)
+{
+    m_surface = cairo_image_surface_create_for_data(
+                            m_buffer, format, m_width, m_height, stride);
+    m_pattern = cairo_pattern_create_for_surface(m_surface);
+}
 
 wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, cairo_surface_t* bitmap ) :
     wxGraphicsObjectRefData( renderer )
@@ -1084,23 +1135,26 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
     wxCHECK_RET( bmp.IsOk(), wxT("Invalid bitmap in wxCairoContext::DrawBitmap"));
 
 #ifdef wxHAS_RAW_BITMAP
-    int bw = m_width = bmp.GetWidth();
-    int bh = m_height = bmp.GetHeight();
-    wxBitmap bmpSource = bmp;  // we need a non-const instance
-    m_buffer = new unsigned char[bw*bh*4];
-    wxUint32* data = (wxUint32*)m_buffer;
-    cairo_format_t bufferFormat;
-
     // Create a surface object and copy the bitmap pixel data to it.  if the
     // image has alpha (or a mask represented as alpha) then we'll use a
     // different format and iterator than if it doesn't...
-    if (bmpSource.GetDepth() == 32 
+    const cairo_format_t bufferFormat = bmp.GetDepth() == 32
 #ifdef __WXGTK__
-            || bmpSource.GetMask()
+                                            || bmp.GetMask()
 #endif
-    )
-    {   // use the bitmap's alpha
-        bufferFormat = CAIRO_FORMAT_ARGB32;
+                                        ? CAIRO_FORMAT_ARGB32
+                                        : CAIRO_FORMAT_RGB24;
+
+    int stride = InitBuffer(bmp.GetWidth(), bmp.GetHeight(), bufferFormat);
+
+    int bw = m_width;
+    int bh = m_height;
+    wxBitmap bmpSource = bmp;  // we need a non-const instance
+    wxUint32* data = (wxUint32*)m_buffer;
+
+    if ( bufferFormat == CAIRO_FORMAT_ARGB32 )
+    {
+        // use the bitmap's alpha
         wxAlphaPixelData pixData(bmpSource, wxPoint(0,0), wxSize(bw, bh));
         wxCHECK_RET( pixData, wxT("Failed to gain raw access to bitmap data."));
 
@@ -1108,6 +1162,7 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
         for (int y=0; y<bh; y++)
         {
             wxAlphaPixelData::Iterator rowStart = p;
+            wxUint32* const rowStartDst = data;
             for (int x=0; x<bw; x++)
             {
                 // Each pixel in CAIRO_FORMAT_ARGB32 is a 32-bit quantity,
@@ -1125,13 +1180,14 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
                 ++data;
                 ++p;
             }
+
+            data = rowStartDst + stride / 4;
             p = rowStart;
             p.OffsetY(pixData, 1);
         }
     }
     else  // no alpha
     {
-        bufferFormat = CAIRO_FORMAT_RGB24;
         wxNativePixelData pixData(bmpSource, wxPoint(0,0), wxSize(bw, bh));
         wxCHECK_RET( pixData, wxT("Failed to gain raw access to bitmap data."));
 
@@ -1139,6 +1195,7 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
         for (int y=0; y<bh; y++)
         {
             wxNativePixelData::Iterator rowStart = p;
+            wxUint32* const rowStartDst = data;
             for (int x=0; x<bw; x++)
             {
                 // Each pixel in CAIRO_FORMAT_RGB24 is a 32-bit quantity, with
@@ -1149,6 +1206,8 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
                 ++data;
                 ++p;
             }
+
+            data = rowStartDst + stride / 4;
             p = rowStart;
             p.OffsetY(pixData, 1);
         }
@@ -1168,6 +1227,7 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
         for (int y=0; y<bh; y++)
         {
             wxNativePixelData::Iterator rowStart = p;
+            wxUint32* const rowStartDst = data;
             for (int x=0; x<bw; x++)
             {
                 if (p.Red()+p.Green()+p.Blue() == 0)
@@ -1177,15 +1237,15 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
                 ++data;
                 ++p;
             }
+
+            data = rowStartDst + stride / 4;
             p = rowStart;
             p.OffsetY(pixData, 1);
         }
     }
 #endif
 
-    m_surface = cairo_image_surface_create_for_data(
-                            m_buffer, bufferFormat, bw, bh, bw*4);
-    m_pattern = cairo_pattern_create_for_surface(m_surface);
+    InitSurface(bufferFormat, stride);
 #endif // wxHAS_RAW_BITMAP
 }