tdf#142061 Add window scaling to XOR emulation on macOS

Window scaling for retina displays on macOS has been added to fix
tdf#138122 in commit 1a167625314bf36b735176ed488e6ba9b5e9b675

Missing window scaling for XOR emulation is added by this change.
Code modified for macOS is moved from quartz/salgidcommon.cxx to
osx/salmacos.cxx while original code is copied to ios/salios.cxx
to prevent modifications for iOS.

Change-Id: Ia8c52f9045379cc37d5aff1279650db0dddee8c0
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115816
Tested-by: Adolfo Jayme Barrientos <fitojb@ubuntu.com>
Reviewed-by: Adolfo Jayme Barrientos <fitojb@ubuntu.com>

1 files changed, 147 insertions, 0 deletions

diff --git a/vcl/ios/salios.cxx b/vcl/ios/salios.cxx
index ac11faff3072..335c14264c64 100644
--- a/vcl/ios/salios.cxx
+++ b/vcl/ios/salios.cxx
@@ -325,6 +325,153 @@ void AquaSalGraphics::SetVirDevGraphics(CGLayerHolder const & rLayer, CGContextR
     maShared.setState();
 }
 
+void XorEmulation::SetTarget( int nWidth, int nHeight, int nTargetDepth,
+                              CGContextRef xTargetContext, CGLayerRef xTargetLayer )
+{
+    SAL_INFO( "vcl.quartz", "XorEmulation::SetTarget() this=" << this <<
+              " (" << nWidth << "x" << nHeight << ") depth=" << nTargetDepth <<
+              " context=" << xTargetContext << " layer=" << xTargetLayer );
+
+    // prepare to replace old mask+temp context
+    if( m_xMaskContext )
+    {
+        // cleanup the mask context
+        CGContextRelease( m_xMaskContext );
+        delete[] m_pMaskBuffer;
+        m_xMaskContext = nullptr;
+        m_pMaskBuffer = nullptr;
+
+        // cleanup the temp context if needed
+        if( m_xTempContext )
+        {
+            CGContextRelease( m_xTempContext );
+            delete[] m_pTempBuffer;
+            m_xTempContext = nullptr;
+            m_pTempBuffer = nullptr;
+        }
+    }
+
+    // return early if there is nothing more to do
+    if( !xTargetContext )
+    {
+        return;
+    }
+    // retarget drawing operations to the XOR mask
+    m_xTargetLayer = xTargetLayer;
+    m_xTargetContext = xTargetContext;
+
+    // prepare creation of matching CGBitmaps
+    CGColorSpaceRef aCGColorSpace = GetSalData()->mxRGBSpace;
+    CGBitmapInfo aCGBmpInfo = kCGImageAlphaNoneSkipFirst;
+    int nBitDepth = nTargetDepth;
+    if( !nBitDepth )
+    {
+        nBitDepth = 32;
+    }
+    int nBytesPerRow = 4;
+    const size_t nBitsPerComponent = (nBitDepth == 16) ? 5 : 8;
+    if( nBitDepth <= 8 )
+    {
+        aCGColorSpace = GetSalData()->mxGraySpace;
+        aCGBmpInfo = kCGImageAlphaNone;
+        nBytesPerRow = 1;
+    }
+    nBytesPerRow *= nWidth;
+    m_nBufferLongs = (nHeight * nBytesPerRow + sizeof(sal_uLong)-1) / sizeof(sal_uLong);
+
+    // create a XorMask context
+    m_pMaskBuffer = new sal_uLong[ m_nBufferLongs ];
+    m_xMaskContext = CGBitmapContextCreate( m_pMaskBuffer,
+                                            nWidth, nHeight,
+                                            nBitsPerComponent, nBytesPerRow,
+                                            aCGColorSpace, aCGBmpInfo );
+    SAL_WARN_IF( !m_xMaskContext, "vcl.quartz", "mask context creation failed" );
+
+    // reset the XOR mask to black
+    memset( m_pMaskBuffer, 0, m_nBufferLongs * sizeof(sal_uLong) );
+
+    // a bitmap context will be needed for manual XORing
+    // create one unless the target context is a bitmap context
+    if( nTargetDepth )
+    {
+        m_pTempBuffer = static_cast<sal_uLong*>(CGBitmapContextGetData( m_xTargetContext ));
+    }
+    if( !m_pTempBuffer )
+    {
+        // create a bitmap context matching to the target context
+        m_pTempBuffer = new sal_uLong[ m_nBufferLongs ];
+        m_xTempContext = CGBitmapContextCreate( m_pTempBuffer,
+                                                nWidth, nHeight,
+                                                nBitsPerComponent, nBytesPerRow,
+                                                aCGColorSpace, aCGBmpInfo );
+        SAL_WARN_IF( !m_xTempContext, "vcl.quartz", "temp context creation failed" );
+    }
+
+    // initialize XOR mask context for drawing
+    CGContextSetFillColorSpace( m_xMaskContext, aCGColorSpace );
+    CGContextSetStrokeColorSpace( m_xMaskContext, aCGColorSpace );
+    CGContextSetShouldAntialias( m_xMaskContext, false );
+
+    // improve the XorMask's XOR emulation a little
+    // NOTE: currently only enabled for monochrome contexts
+    if( aCGColorSpace == GetSalData()->mxGraySpace )
+    {
+        CGContextSetBlendMode( m_xMaskContext, kCGBlendModeDifference );
+    }
+    // initialize the transformation matrix to the drawing target
+    const CGAffineTransform aCTM = CGContextGetCTM( xTargetContext );
+    CGContextConcatCTM( m_xMaskContext, aCTM );
+    if( m_xTempContext )
+    {
+        CGContextConcatCTM( m_xTempContext, aCTM );
+    }
+    // initialize the default XorMask graphics state
+    CGContextSaveGState( m_xMaskContext );
+}
+
+bool XorEmulation::UpdateTarget()
+{
+    SAL_INFO( "vcl.quartz", "XorEmulation::UpdateTarget() this=" << this );
+
+    if( !IsEnabled() )
+    {
+        return false;
+    }
+    // update the temp bitmap buffer if needed
+    if( m_xTempContext )
+    {
+        SAL_WARN_IF( m_xTargetContext == nullptr, "vcl.quartz", "Target layer is NULL");
+        CGContextDrawLayerAtPoint( m_xTempContext, CGPointZero, m_xTargetLayer );
+    }
+    // do a manual XOR with the XorMask
+    // this approach suffices for simple color manipulations
+    // and also the complex-clipping-XOR-trick used in metafiles
+    const sal_uLong* pSrc = m_pMaskBuffer;
+    sal_uLong* pDst = m_pTempBuffer;
+    for( int i = m_nBufferLongs; --i >= 0;)
+    {
+        *(pDst++) ^= *(pSrc++);
+    }
+    // write back the XOR results to the target context
+    if( m_xTempContext )
+    {
+        CGImageRef xXorImage = CGBitmapContextCreateImage( m_xTempContext );
+        const int nWidth  = static_cast<int>(CGImageGetWidth( xXorImage ));
+        const int nHeight = static_cast<int>(CGImageGetHeight( xXorImage ));
+        // TODO: update minimal changerect
+        const CGRect aFullRect = CGRectMake(0, 0, nWidth, nHeight);
+        CGContextDrawImage( m_xTargetContext, aFullRect, xXorImage );
+        CGImageRelease( xXorImage );
+    }
+
+    // reset the XorMask to black again
+    // TODO: not needed for last update
+    memset( m_pMaskBuffer, 0, m_nBufferLongs * sizeof(sal_uLong) );
+
+    // TODO: return FALSE if target was not changed
+    return true;
+}
+
 /// From salvd.cxx
 
 void AquaSalVirtualDevice::Destroy()