tdf#133716: Fix edge gradient when upscaling image

When an image is getting upscaled with cario as engine it got blured borders.
The issue that was worked on showed, in the PresenterConsole, that the
borders of the previews and control area had an unnecessary gradient in it.
As these borders are build from images which are getting upscaled,
either in width or height a graident ocurred. This was because the cairo
rending didn't had the correct pattern extention set: CAIRO_EXTEND_PAD.

Nearly same issue also occured when adding an image to a presentation
and upscaling it, the borders got blured. For images with either height or
width equal to one this was a while back fixed: tdf#114117, but not for the
general case. Using another extend mode fixes this, because the PAD
extend mode doesn't blur the borders.

CAIRO_EXTEND_PAD:
pixels outside of the pattern copy the closest pixel from the source

Change-Id: I39f8a14a69f035a43a93afb303f0a2e7ec8699c7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/134325
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

2 files changed, 17 insertions, 22 deletions

diff --git a/vcl/headless/CairoCommon.cxx b/vcl/headless/CairoCommon.cxx
index 73a6b72f802e..9897334d4532 100644
--- a/vcl/headless/CairoCommon.cxx
+++ b/vcl/headless/CairoCommon.cxx
@@ -876,12 +876,11 @@ basegfx::B2DRange renderWithOperator(cairo_t* cr, const SalTwoRect& rTR, cairo_s
 
     cairo_save(cr);
     cairo_set_source_surface(cr, source, -rTR.mnSrcX, -rTR.mnSrcY);
-    if ((fXScale != 1.0 && rTR.mnSrcWidth == 1) || (fYScale != 1.0 && rTR.mnSrcHeight == 1))
-    {
-        cairo_pattern_t* sourcepattern = cairo_get_source(cr);
-        cairo_pattern_set_extend(sourcepattern, CAIRO_EXTEND_REPEAT);
-        cairo_pattern_set_filter(sourcepattern, CAIRO_FILTER_NEAREST);
-    }
+
+    //tdf#133716 borders of upscaled images should not be blured
+    cairo_pattern_t* sourcepattern = cairo_get_source(cr);
+    cairo_pattern_set_extend(sourcepattern, CAIRO_EXTEND_PAD);
+
     cairo_set_operator(cr, eOperator);
     cairo_paint(cr);
     cairo_restore(cr);
diff --git a/vcl/headless/SvpGraphicsBackend.cxx b/vcl/headless/SvpGraphicsBackend.cxx
index 14a9a017ed94..0566f444013d 100644
--- a/vcl/headless/SvpGraphicsBackend.cxx
+++ b/vcl/headless/SvpGraphicsBackend.cxx
@@ -488,12 +488,11 @@ void SvpGraphicsBackend::drawMask(const SalTwoRect& rTR, const SalBitmap& rSalBi
     double fYScale = static_cast<double>(rTR.mnDestHeight) / rTR.mnSrcHeight;
     cairo_scale(cr, fXScale, fYScale);
     cairo_set_source_surface(cr, aSurface.getSurface(), -rTR.mnSrcX, -rTR.mnSrcY);
-    if ((fXScale != 1.0 && rTR.mnSrcWidth == 1) || (fYScale != 1.0 && rTR.mnSrcHeight == 1))
-    {
-        cairo_pattern_t* sourcepattern = cairo_get_source(cr);
-        cairo_pattern_set_extend(sourcepattern, CAIRO_EXTEND_REPEAT);
-        cairo_pattern_set_filter(sourcepattern, CAIRO_FILTER_NEAREST);
-    }
+
+    //tdf#133716 borders of upscaled images should not be blured
+    cairo_pattern_t* sourcepattern = cairo_get_source(cr);
+    cairo_pattern_set_extend(sourcepattern, CAIRO_EXTEND_PAD);
+
     cairo_paint(cr);
 
     m_rCairoCommon.releaseCairoContext(cr, false, extents);
@@ -674,16 +673,13 @@ bool SvpGraphicsBackend::drawAlphaBitmap(const SalTwoRect& rTR, const SalBitmap&
     cairo_scale(cr, fXScale, fYScale);
     cairo_set_source_surface(cr, source, -rTR.mnSrcX, -rTR.mnSrcY);
 
-    //tdf#114117 when stretching a single pixel width/height source to fit an area
-    //set extend and filter to stretch it with simplest expected interpolation
-    if ((fXScale != 1.0 && rTR.mnSrcWidth == 1) || (fYScale != 1.0 && rTR.mnSrcHeight == 1))
-    {
-        cairo_pattern_t* sourcepattern = cairo_get_source(cr);
-        cairo_pattern_set_extend(sourcepattern, CAIRO_EXTEND_REPEAT);
-        cairo_pattern_set_filter(sourcepattern, CAIRO_FILTER_NEAREST);
-        cairo_pattern_set_extend(maskpattern, CAIRO_EXTEND_REPEAT);
-        cairo_pattern_set_filter(maskpattern, CAIRO_FILTER_NEAREST);
-    }
+    cairo_pattern_t* sourcepattern = cairo_get_source(cr);
+
+    //tdf#133716 borders of upscaled images should not be blured
+    //tdf#114117 when stretching a single or multi pixel width/height source to fit an area
+    //the image will be extended into that size.
+    cairo_pattern_set_extend(sourcepattern, CAIRO_EXTEND_PAD);
+    cairo_pattern_set_extend(maskpattern, CAIRO_EXTEND_PAD);
 
     //this block is just "cairo_mask_surface", but we have to make it explicit
     //because of the cairo_pattern_set_filter etc we may want applied