From dfe76430cc5634ff611a08671e83fe9d8089cfdf Mon Sep 17 00:00:00 2001
From: Maarten Bent <MaartenBent@users.noreply.github.com>
Date: Sun, 11 Aug 2019 18:25:09 +0200
Subject: [PATCH] Implement GradientFillLinear and GradientFillConcentric for
 wxSVGFileDC

---
 include/wx/dcsvg.h   | 13 +++++++
 src/common/dcsvg.cpp | 82 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/include/wx/dcsvg.h b/include/wx/dcsvg.h
index 4773c6152c..d0176c2295 100644
--- a/include/wx/dcsvg.h
+++ b/include/wx/dcsvg.h
@@ -220,6 +220,16 @@ private:
         return false;
     }
 
+    virtual void DoGradientFillLinear(const wxRect& rect,
+                                      const wxColour& initialColour,
+                                      const wxColour& destColour,
+                                      wxDirection nDirection = wxEAST) wxOVERRIDE;
+
+    virtual void DoGradientFillConcentric(const wxRect& rect,
+                                        const wxColour& initialColour,
+                                        const wxColour& destColour,
+                                        const wxPoint& circleCenter) wxOVERRIDE;
+
     virtual void DoGetSize(int * x, int *y) const wxOVERRIDE
     {
         if ( x )
@@ -276,6 +286,9 @@ private:
     // incremented in each SetClippingRegion() call.
     size_t m_clipUniqueId;
 
+    // Unique ID for every gradient.
+    size_t m_gradientUniqueId;
+
     wxDECLARE_ABSTRACT_CLASS(wxSVGFileDCImpl);
     wxDECLARE_NO_COPY_CLASS(wxSVGFileDCImpl);
 };
diff --git a/src/common/dcsvg.cpp b/src/common/dcsvg.cpp
index a02bbd6f5b..422b36b6c4 100644
--- a/src/common/dcsvg.cpp
+++ b/src/common/dcsvg.cpp
@@ -500,6 +500,8 @@ void wxSVGFileDCImpl::Init(const wxString &filename, int Width, int Height,
     m_clipUniqueId = 0;
     m_clipNestingLevel = 0;
 
+    m_gradientUniqueId = 0;
+
     m_mm_to_pix_x = dpi / 25.4;
     m_mm_to_pix_y = dpi / 25.4;
 
@@ -1015,6 +1017,86 @@ void wxSVGFileDCImpl::DoDrawEllipticArc(wxCoord x, wxCoord y, wxCoord w, wxCoord
     write(arcLine);
 }
 
+void wxSVGFileDCImpl::DoGradientFillLinear(const wxRect& rect,
+                                           const wxColour& initialColour,
+                                           const wxColour& destColour,
+                                           wxDirection nDirection)
+{
+    NewGraphicsIfNeeded();
+
+    float initOpacity;
+    float destOpacity;
+    wxString initCol = Col2SVG(initialColour, &initOpacity);
+    wxString destCol = Col2SVG(destColour, &destOpacity);
+
+    const int x1 = ((nDirection & wxLEFT) > 0) ? 100 : 0;
+    const int y1 = ((nDirection & wxUP) > 0) ? 100 : 0;
+    const int x2 = ((nDirection & wxRIGHT) > 0) ? 100 : 0;
+    const int y2 = ((nDirection & wxDOWN) > 0) ? 100 : 0;
+
+    wxString s;
+    s += wxS("  <defs>\n");
+    s += wxString::Format(wxS("    <linearGradient id=\"gradient%zu\" x1=\"%d%%\" y1=\"%d%%\" x2=\"%d%%\" y2=\"%d%%\">\n"),
+        m_gradientUniqueId, x1, y1, x2, y2);
+    s += wxString::Format(wxS("      <stop offset=\"0%%\" style=\"stop-color:%s; stop-opacity:%s\"/>\n"),
+        initCol, NumStr(initOpacity));
+    s += wxString::Format(wxS("      <stop offset=\"100%%\" style=\"stop-color:%s; stop-opacity:%s\"/>\n"),
+        destCol, NumStr(destOpacity));
+    s += wxS("    </linearGradient>\n");
+    s += wxS("  </defs>\n");
+
+    s += wxString::Format(wxS("  <rect x=\"%d\" y=\"%d\" width=\"%d\" height=\"%d\" fill=\"url(#gradient%zu)\" %s %s %s/>\n"),
+        rect.x, rect.y, rect.width, rect.height, m_gradientUniqueId,
+        wxRenderMode(m_renderingMode), wxGetPenPattern(m_pen), wxGetBrushFill(m_brush));
+
+    m_gradientUniqueId++;
+
+    write(s);
+
+    CalcBoundingBox(rect.x, rect.y);
+    CalcBoundingBox(rect.x + rect.width, rect.y + rect.height);
+}
+
+void wxSVGFileDCImpl::DoGradientFillConcentric(const wxRect& rect,
+                                               const wxColour& initialColour,
+                                               const wxColour& destColour,
+                                               const wxPoint& circleCenter)
+{
+    NewGraphicsIfNeeded();
+
+    float initOpacity;
+    float destOpacity;
+    wxString initCol = Col2SVG(initialColour, &initOpacity);
+    wxString destCol = Col2SVG(destColour, &destOpacity);
+
+    const double cx = circleCenter.x * 100.0 / rect.GetWidth();
+    const double cy = circleCenter.y * 100.0 / rect.GetHeight();
+    const double fx = cx;
+    const double fd = cy;
+
+    wxString s;
+    s += wxS("  <defs>\n");
+    s += wxString::Format(wxS("    <radialGradient id=\"gradient%zu\" cx=\"%s%%\" cy=\"%s%%\" fx=\"%s%%\" fy=\"%s%%\">\n"),
+        m_gradientUniqueId, NumStr(cx), NumStr(cy), NumStr(fx), NumStr(fd));
+    s += wxString::Format(wxS("      <stop offset=\"0%%\" style=\"stop-color:%s; stop-opacity:%s\" />\n"),
+        initCol, NumStr(initOpacity));
+    s += wxString::Format(wxS("      <stop offset=\"100%%\" style=\"stop-color:%s; stop-opacity:%s\" />\n"),
+        destCol, NumStr(destOpacity));
+    s += wxS("    </radialGradient>\n");
+    s += wxS("  </defs>\n");
+
+    s += wxString::Format(wxS("  <rect x=\"%d\" y=\"%d\" width=\"%d\" height=\"%d\" fill=\"url(#gradient%zu)\" %s %s %s/>\n"),
+        rect.x, rect.y, rect.width, rect.height, m_gradientUniqueId,
+        wxRenderMode(m_renderingMode), wxGetPenPattern(m_pen), wxGetBrushFill(m_brush));
+
+    m_gradientUniqueId++;
+
+    write(s);
+
+    CalcBoundingBox(rect.x, rect.y);
+    CalcBoundingBox(rect.x + rect.width, rect.y + rect.height);
+}
+
 void wxSVGFileDCImpl::DoSetClippingRegion(int x, int y, int width, int height)
 {
     wxString svg;