From 1311aa610c13552f750bfe93ce2c0cf4c01c4f51 Mon Sep 17 00:00:00 2001
From: andrew <andrew@lazarus-ide.org>
Date: Sat, 11 Jan 2014 04:23:00 +0000
Subject: [PATCH] gtk3 added polybezier

git-svn-id: trunk@43701 -
---
 lcl/interfaces/gtk3/gtk3objects.pas | 46 +++++++++++++++++++++++++++++
 lcl/interfaces/gtk3/gtk3winapi.inc  |  8 ++---
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/lcl/interfaces/gtk3/gtk3objects.pas b/lcl/interfaces/gtk3/gtk3objects.pas
index 36db98fba3..61dcfa9d8c 100644
--- a/lcl/interfaces/gtk3/gtk3objects.pas
+++ b/lcl/interfaces/gtk3/gtk3objects.pas
@@ -236,6 +236,7 @@ type
     procedure drawPixmap(p: PPoint; pm: PGdkPixbuf; sr: PRect);
     procedure drawPolyLine(P: PPoint; NumPts: Integer);
     procedure drawPolygon(P: PPoint; NumPts: Integer; FillRule: integer);
+    procedure drawPolyBezier(P: PPoint; NumPoints: Integer; Filled, Continuous: boolean);
     procedure EllipseArcPath(CX, CY, RX, RY: Double; Angle1, Angle2: Double; Clockwise, Continuous: Boolean);
     procedure eraseRect(ARect: PRect);
     procedure fillRect(ARect: PRect; ABrush: HBRUSH); overload;
@@ -1402,6 +1403,51 @@ begin
   end;
 end;
 
+procedure TGtk3DeviceContext.drawPolyBezier(P: PPoint; NumPoints: Integer; Filled, Continuous: boolean);
+var
+  i: Integer;
+const
+  PixelOffset = 0.5;
+begin
+  // 3 points per curve + a starting point for the first curve
+  if (NumPoints < 4) then
+    Exit;
+
+  cairo_save(Widget);
+  try
+    ApplyPen;
+    cairo_move_to(Widget, P[0].X+PixelOffset, P[0].Y+PixelOffset); // start point
+    i := 1;
+
+    // we need 3 points left for continuous and 4 for not continous
+    while i < NumPoints-1 - (3 + ord(not Continuous)) do
+    begin
+      if Not Continuous then
+      begin
+        cairo_move_to(Widget, P[i].X+PixelOffset, P[i].Y+PixelOffset); // start point
+        Inc(i);
+      end;
+      cairo_curve_to(Widget,
+                     P[i].X+PixelOffset, P[i].Y+PixelOffset, // control point 1
+                     P[i+1].X+PixelOffset, P[i+1].Y+PixelOffset, // control point 2
+                     P[i+2].X+PixelOffset, P[i+2].Y+PixelOffset); // end point and start point of next
+      Inc(i, 3);
+    end;
+    cairo_stroke_preserve(Widget);
+
+    if Filled then
+    begin
+      ApplyBrush;
+      // join start and end points
+      cairo_close_path(Widget);
+      cairo_fill(Widget);
+    end;
+
+  finally
+    cairo_restore(Widget);
+  end;
+end;
+
 procedure TGtk3DeviceContext.eraseRect(ARect: PRect);
 begin
   // cairo_surface_
diff --git a/lcl/interfaces/gtk3/gtk3winapi.inc b/lcl/interfaces/gtk3/gtk3winapi.inc
index 4beff2fe63..762c9391ec 100644
--- a/lcl/interfaces/gtk3/gtk3winapi.inc
+++ b/lcl/interfaces/gtk3/gtk3winapi.inc
@@ -3081,10 +3081,10 @@ end;
 function TGtk3WidgetSet.PolyBezier(DC: HDC; Points: PPoint; NumPts: Integer;
   Filled, Continuous: boolean): boolean;
 begin
-  {$IFDEF GTK3DEBUGNOTIMPLEMENTED}
-  DebugLn('WARNING: TGtk3WidgetSet.PolyBezier not implemented ...');
-  {$ENDIF}
-  Result:=inherited PolyBezier(DC, Points, NumPts, Filled, Continuous);
+  if not IsValidDC(DC) then
+    exit(False);
+  TGtk3DeviceContext(DC).drawPolyBezier(Points, NumPts, Filled, Continuous);
+  Result:=True;
 end;
 
 function TGtk3WidgetSet.Polygon(DC: HDC; Points: PPoint; NumPts: Integer;