widget theme: Gradient support when drawing widgets

Change-Id: I29239348e36e4963d9708a22ac649b2b1d68bf02
Reviewed-on: https://gerrit.libreoffice.org/82207
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

6 files changed, 132 insertions, 0 deletions

diff --git a/vcl/headless/svpgdi.cxx b/vcl/headless/svpgdi.cxx
index 5c1f0daab194..57f66d4fabf6 100644
--- a/vcl/headless/svpgdi.cxx
+++ b/vcl/headless/svpgdi.cxx
@@ -32,6 +32,7 @@
 #include <o3tl/safeint.hxx>
 #include <vcl/BitmapTools.hxx>
 #include <vcl/sysdata.hxx>
+#include <vcl/gradient.hxx>
 #include <config_cairo_canvas.h>
 #include <basegfx/numeric/ftools.hxx>
 #include <basegfx/range/b2drange.hxx>
@@ -1494,6 +1495,39 @@ bool SvpSalGraphics::drawPolyPolygon(
     return true;
 }
 
+bool SvpSalGraphics::implDrawGradient(basegfx::B2DPolyPolygon const & rPolyPolygon, SalGradient const & rGradient)
+{
+    cairo_t* cr = getCairoContext(true);
+    clipRegion(cr);
+
+    basegfx::B2DHomMatrix rObjectToDevice;
+
+    for (auto const & rPolygon : rPolyPolygon)
+        AddPolygonToPath(cr, rPolygon, rObjectToDevice, !getAntiAliasB2DDraw(), false);
+
+    cairo_pattern_t* pattern;
+    pattern = cairo_pattern_create_linear(rGradient.maPoint1.getX(), rGradient.maPoint1.getY(), rGradient.maPoint2.getX(), rGradient.maPoint2.getY());
+
+    for (SalGradientStop const & rStop : rGradient.maStops)
+    {
+        double r = rStop.maColor.GetRed() / 255.0;
+        double g = rStop.maColor.GetGreen() / 255.0;
+        double b = rStop.maColor.GetBlue() / 255.0;
+        double a = (0xFF - rStop.maColor.GetTransparency()) / 255.0;
+        double offset = rStop.mfOffset;
+
+        cairo_pattern_add_color_stop_rgba(pattern, offset, r, g, b, a);
+    }
+    cairo_set_source(cr, pattern);
+
+    basegfx::B2DRange extents = getClippedFillDamage(cr);
+    cairo_fill_preserve(cr);
+
+    releaseCairoContext(cr, true, extents);
+
+    return true;
+}
+
 void SvpSalGraphics::applyColor(cairo_t *cr, Color aColor, double fTransparency)
 {
     if (cairo_surface_get_content(m_pSurface) == CAIRO_CONTENT_COLOR_ALPHA)
diff --git a/vcl/inc/SalGradient.hxx b/vcl/inc/SalGradient.hxx
new file mode 100644
index 000000000000..1b4a47f9a6ff
--- /dev/null
+++ b/vcl/inc/SalGradient.hxx
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_VCL_INC_SALGRADIENT_HXX
+#define INCLUDED_VCL_INC_SALGRADIENT_HXX
+
+#include <basegfx/point/b2dpoint.hxx>
+
+struct SalGradientStop
+{
+    Color maColor;
+    float mfOffset;
+
+    SalGradientStop(Color const& rColor, float fOffset)
+        : maColor(rColor)
+        , mfOffset(fOffset)
+    {
+    }
+};
+
+struct SalGradient
+{
+    basegfx::B2DPoint maPoint1;
+    basegfx::B2DPoint maPoint2;
+    std::vector<SalGradientStop> maStops;
+};
+
+#endif // INCLUDED_VCL_INC_SALGRADIENT_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/inc/headless/svpgdi.hxx b/vcl/inc/headless/svpgdi.hxx
index b0e4aac4adad..d06c138a0284 100644
--- a/vcl/inc/headless/svpgdi.hxx
+++ b/vcl/inc/headless/svpgdi.hxx
@@ -232,6 +232,8 @@ public:
                                                    const PolyFlags* const* pFlgAry ) override;
     virtual bool            drawGradient( const tools::PolyPolygon&, const Gradient& ) override { return false; };
 
+    virtual bool implDrawGradient(basegfx::B2DPolyPolygon const & rPolyPolygon, SalGradient const & rGradient) override;
+
     virtual void            copyArea( long nDestX,
                                       long nDestY,
                                       long nSrcX,
diff --git a/vcl/inc/salgdi.hxx b/vcl/inc/salgdi.hxx
index d61c00cd9654..6b5899a4ce10 100644
--- a/vcl/inc/salgdi.hxx
+++ b/vcl/inc/salgdi.hxx
@@ -25,6 +25,7 @@
 #include "impfontmetricdata.hxx"
 #include "salgdiimpl.hxx"
 #include "sallayout.hxx"
+#include "SalGradient.hxx"
 #include <basegfx/matrix/b2dhommatrix.hxx>
 #include "WidgetDrawInterface.hxx"
 
@@ -275,6 +276,8 @@ public:
                                     const tools::PolyPolygon& rPolyPoly,
                                     const Gradient& rGradient );
 
+    bool DrawGradient(basegfx::B2DPolyPolygon const & rPolyPolygon,
+                      SalGradient const & rGradient);
 
     // CopyArea --> No RasterOp, but ClipRegion
     void                        CopyArea(
@@ -486,6 +489,12 @@ protected:
                                     const tools::PolyPolygon& rPolyPoly,
                                     const Gradient& rGradient ) = 0;
 
+    virtual bool implDrawGradient(basegfx::B2DPolyPolygon const & /*rPolyPolygon*/,
+                                  SalGradient const & /*rGradient*/)
+    {
+        return false;
+    }
+
     // CopyArea --> No RasterOp, but ClipRegion
     virtual void                copyArea(
                                     long nDestX, long nDestY,
diff --git a/vcl/source/gdi/FileDefinitionWidgetDraw.cxx b/vcl/source/gdi/FileDefinitionWidgetDraw.cxx
index 653a369a1e3d..40d443bb0edf 100644
--- a/vcl/source/gdi/FileDefinitionWidgetDraw.cxx
+++ b/vcl/source/gdi/FileDefinitionWidgetDraw.cxx
@@ -19,11 +19,13 @@
 
 #include <basegfx/range/b2drectangle.hxx>
 #include <basegfx/polygon/b2dpolygontools.hxx>
+#include <basegfx/tuple/b2dtuple.hxx>
 #include <basegfx/matrix/b2dhommatrixtools.hxx>
 
 #include <tools/stream.hxx>
 #include <vcl/bitmapex.hxx>
 #include <vcl/BitmapTools.hxx>
+#include <vcl/gradient.hxx>
 
 #include <comphelper/seqstream.hxx>
 #include <comphelper/processfactory.hxx>
@@ -221,6 +223,50 @@ void drawFromDrawCommands(gfx::DrawRoot const& rDrawRoot, SalGraphics& rGraphics
                                               basegfx::B2DPolyPolygon(aB2DPolygon),
                                               1.0 - rRectangle.mnOpacity, nullptr);
                 }
+                else if (rRectangle.mpFillGradient)
+                {
+                    rGraphics.SetLineColor();
+                    rGraphics.SetFillColor();
+                    if (rRectangle.mpFillGradient->meType == gfx::GradientType::Linear)
+                    {
+                        auto* pLinearGradient = static_cast<gfx::LinearGradientInfo*>(
+                            rRectangle.mpFillGradient.get());
+                        SalGradient aGradient;
+                        double x, y;
+
+                        x = pLinearGradient->x1;
+                        y = pLinearGradient->y1;
+
+                        if (x > aSVGRect.getCenterX())
+                            x = x + fDeltaX;
+                        if (y > aSVGRect.getCenterY())
+                            y = y + fDeltaY;
+
+                        aGradient.maPoint1 = basegfx::B2DPoint(x, y);
+                        aGradient.maPoint1 *= basegfx::utils::createTranslateB2DHomMatrix(
+                            aTargetSurface.getMinX() - 0.5, aTargetSurface.getMinY() - 0.5);
+
+                        x = pLinearGradient->x2;
+                        y = pLinearGradient->y2;
+
+                        if (x > aSVGRect.getCenterX())
+                            x = x + fDeltaX;
+                        if (y > aSVGRect.getCenterY())
+                            y = y + fDeltaY;
+
+                        aGradient.maPoint2 = basegfx::B2DPoint(x, y);
+                        aGradient.maPoint2 *= basegfx::utils::createTranslateB2DHomMatrix(
+                            aTargetSurface.getMinX() - 0.5, aTargetSurface.getMinY() - 0.5);
+
+                        for (gfx::GradientStop const& rStop : pLinearGradient->maGradientStops)
+                        {
+                            Color aColor(rStop.maColor);
+                            aColor.SetTransparency(rStop.mfOpacity * (1.0f - rRectangle.mnOpacity));
+                            aGradient.maStops.emplace_back(aColor, rStop.mfOffset);
+                        }
+                        rGraphics.DrawGradient(basegfx::B2DPolyPolygon(aB2DPolygon), aGradient);
+                    }
+                }
                 if (rRectangle.mpStrokeColor)
                 {
                     rGraphics.SetLineColor(Color(*rRectangle.mpStrokeColor));
diff --git a/vcl/source/gdi/salgdilayout.cxx b/vcl/source/gdi/salgdilayout.cxx
index c3c3c306d19e..b0fefa665bd5 100644
--- a/vcl/source/gdi/salgdilayout.cxx
+++ b/vcl/source/gdi/salgdilayout.cxx
@@ -652,6 +652,11 @@ bool SalGraphics::DrawGradient( const tools::PolyPolygon& rPolyPoly, const Gradi
     return drawGradient( rPolyPoly, rGradient );
 }
 
+bool SalGraphics::DrawGradient(basegfx::B2DPolyPolygon const & rPolyPolygon, SalGradient const & rSalGradient)
+{
+    return implDrawGradient(rPolyPolygon, rSalGradient);
+}
+
 void SalGraphics::CopyArea( long nDestX, long nDestY,
                             long nSrcX, long nSrcY,
                             long nSrcWidth, long nSrcHeight,