avmedia: move BitmapWriteAccess inside Bitmap

part of a larger project to hide BitmapWriteAccess inside Bitmap

Change-Id: Ia46c12b3297107892a6236633c11ca9ada6edbd4
Reviewed-on: https://gerrit.libreoffice.org/49106Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>

avmedia/source/gstreamer/gstframegrabber.cxx

@@ -174,24 +174,7 @@ uno::Reference< graphic::XGraphic > SAL_CALL FrameGrabber::grabFrame( double fMe
 
         int nStride = GST_ROUND_UP_4( nWidth * 3 );
         Bitmap aBmp( Size( nWidth, nHeight ), 24 );
-
-        BitmapWriteAccess *pWrite = aBmp.AcquireWriteAccess();
-        if( pWrite )
-        {
-            // yet another cheesy pixel copying loop
-            for( int y = 0; y < nHeight; ++y )
-            {
-                sal_uInt8 *p = pData + y * nStride;
-                Scanline pScanline = pWrite->GetScanline(y);
-                for (int x = 0; x < nWidth; ++x)
-                {
-                    BitmapColor col(p[0], p[1], p[2]);
-                    pWrite->SetPixelOnData(pScanline, x, col);
-                    p += 3;
-                }
-            }
-        }
-        Bitmap::ReleaseAccess( pWrite );
+        aBmp.SetToData( pData, nStride );
 
 #ifndef AVMEDIA_GST_0_10
         gst_buffer_unmap( pBuf, &aMapInfo );

include/vcl/bitmap.hxx

@@ -650,6 +650,16 @@ public:
                                 BmpFilter eFilter,
                                 const BmpFilterParam* pFilterParam = nullptr );
 
+    /** Copy block of image data into the bitmap.
+        Assumes that the Bitmap has been constructed with the desired size.
+
+        @param pData
+        The block of data to copy
+        @param nStride
+        The number of bytes in a scanline, must >= width
+     */
+    void                    SetToData( sal_uInt8 const *pData, sal_Int32 nStride );
+
 public:
 
     SAL_DLLPRIVATE void     ImplMakeUnique();

vcl/source/gdi/bitmap4.cxx

@@ -22,6 +22,7 @@
 #include <osl/diagnose.h>
 #include <vcl/bitmapaccess.hxx>
 #include <vcl/bitmap.hxx>
+#include <impbmp.hxx>
 
 #define S2(a,b)             { long t; if( ( t = b - a ) < 0 ) { a += t; b -= t; } }
 #define MN3(a,b,c)          S2(a,b); S2(a,c);
@@ -111,6 +112,32 @@ bool Bitmap::Filter( BmpFilter eFilter, const BmpFilterParam* pFilterParam )
     return bRet;
 }
 
+void Bitmap::SetToData( sal_uInt8 const *pData, sal_Int32 nStride )
+{
+    assert(mxImpBmp);
+    auto nWidth = mxImpBmp->ImplGetSize().getWidth();
+    auto nHeight = mxImpBmp->ImplGetSize().getHeight();
+    assert(nStride >= nWidth);
+
+    BitmapWriteAccess *pWrite = AcquireWriteAccess();
+    assert(pWrite);
+    if( pWrite )
+    {
+        for( long y = 0; y < nHeight; ++y )
+        {
+            sal_uInt8 const *p = pData + y * nStride;
+            Scanline pScanline = pWrite->GetScanline(y);
+            for (long x = 0; x < nWidth; ++x)
+            {
+                BitmapColor col(p[0], p[1], p[2]);
+                pWrite->SetPixelOnData(pScanline, x, col);
+                p += 3;
+            }
+        }
+    }
+    ReleaseAccess( pWrite );
+}
+
 bool Bitmap::ImplConvolute3( const long* pMatrix )
 {
     const long          nDivisor = 8;