Started bringing the new drawing code over to the other backends.

gtkarea/main.c

@@ -17,77 +17,216 @@ static GtkWidget *textstr;
 
 static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *p)
 {
+	uiDrawPath *path;
+	uiDrawBrush brush;
 	uiDrawStrokeParams sp;
 
-	uiDrawBeginPathRGB(p->Context, 0xFF, 0x00, 0x00);
+	brush.Type = uiDrawBrushTypeSolid;
-	uiDrawMoveTo(p->Context, p->ClipX + 5, p->ClipY + 5);
+	brush.A = 1;
-	uiDrawLineTo(p->Context, (p->ClipX + p->ClipWidth) - 5, (p->ClipY + p->ClipHeight) - 5);
+
+	brush.R = 1;
+	brush.G = 0;
+	brush.B = 0;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, p->ClipX + 5, p->ClipY + 5);
+	uiDrawPathLineTo(path, (p->ClipX + p->ClipWidth) - 5, (p->ClipY + p->ClipHeight) - 5);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGB(p->Context, 0x00, 0x00, 0xC0);
+	brush.R = 0;
-	uiDrawMoveTo(p->Context, p->ClipX, p->ClipY);
+	brush.G = 0;
-	uiDrawLineTo(p->Context, p->ClipX + p->ClipWidth, p->ClipY);
+	brush.B = 0.75;
-	uiDrawLineTo(p->Context, 50, 150);
+	path = uiDrawNewPath(uiDrawFillModeWinding);
-	uiDrawLineTo(p->Context, 50, 50);
+	uiDrawPathNewFigure(path, p->ClipX, p->ClipY);
-	uiDrawCloseFigure(p->Context);
+	uiDrawPathLineTo(path, p->ClipX + p->ClipWidth, p->ClipY);
+	uiDrawPathLineTo(path, 50, 150);
+	uiDrawPathLineTo(path, 50, 50);
+	uiDrawPathCloseFigure(path);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinRound;
 	sp.Thickness = 5;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGBA(p->Context, 0x00, 0xC0, 0x00, 0x80);
+	brush.R = 0;
-	uiDrawRectangle(p->Context, 120, 80, 50, 50);
+	brush.G = 0.75;
-	uiDrawFill(p->Context, uiDrawFillModeWinding);
+	brush.B = 0;
+	brush.A = 0.5;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathAddRectangle(path, 120, 80, 50, 50);
+	uiDrawPathEnd(path);
+	uiDrawFill(p->Context, path, &brush);
+	uiDrawFreePath(path);
+	brush.A = 1;
 
-	uiDrawBeginPathRGB(p->Context, 0x00, 0x80, 0x00);
+	brush.R = 0;
-	uiDrawMoveTo(p->Context, 5, 10);
+	brush.G = 0.5;
-	uiDrawLineTo(p->Context, 5, 50);
+	brush.B = 0;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 5.5, 10.5);
+	uiDrawPathLineTo(path, 5.5, 50.5);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGB(p->Context, 0x80, 0xC0, 0x00);
+	brush.R = 0.5;
-	uiDrawMoveTo(p->Context, 400, 100);
+	brush.G = 0.75;
-	uiDrawArcTo(p->Context,
+	brush.B = 0;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 400, 100);
+	uiDrawPathArcTo(path,
 		400, 100,
 		50,
 		30. * (M_PI / 180.),
 		// note the end angle here
 		// in GDI, the second angle to AngleArc() is relative to the start, not to 0
-		330. * (M_PI / 180.),
+		330. * (M_PI / 180.));
-		1);
 	// TODO add a checkbox for this
-	uiDrawLineTo(p->Context, 400, 100);
+	uiDrawPathLineTo(path, 400, 100);
-	uiDrawArcTo(p->Context,
+	uiDrawPathNewFigureWithArc(path,
 		510, 100,
 		50,
 		30. * (M_PI / 180.),
-		330. * (M_PI / 180.),
+		330. * (M_PI / 180.));
-		0);
+	uiDrawPathCloseFigure(path);
-	uiDrawCloseFigure(p->Context);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGB(p->Context, 0x00, 0x80, 0xC0);
+	brush.R = 0;
-	uiDrawMoveTo(p->Context, 300, 300);
+	brush.G = 0.5;
-	uiDrawBezierTo(p->Context,
+	brush.B = 0.75;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 300, 300);
+	uiDrawPathBezierTo(path,
 		350, 320,
 		310, 390,
 		435, 372);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
+
+	// based on https://msdn.microsoft.com/en-us/library/windows/desktop/dd756682%28v=vs.85%29.aspx
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+#define XO 50
+#define YO 250
+	uiDrawPathNewFigure(path, 0 + XO, 0 + YO);
+	uiDrawPathLineTo(path, 200 + XO, 0 + YO);
+	uiDrawPathBezierTo(path,
+		150 + XO, 50 + YO,
+		150 + XO, 150 + YO,
+		200 + XO, 200 + YO);
+	uiDrawPathLineTo(path, 0 + XO, 200 + YO);
+	uiDrawPathBezierTo(path,
+		50 + XO, 150 + YO,
+		50 + XO, 50 + YO,
+		0 + XO, 0 + YO);
+	uiDrawPathCloseFigure(path);
+	uiDrawPathEnd(path);
+	// first the stroke
+	brush.Type = uiDrawBrushTypeSolid;
+	brush.R = 0;
+	brush.G = 0;
+	brush.B = 0;
+	brush.A = 1;
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.MiterLimit = uiDrawDefaultMiterLimit;
+	sp.Thickness = 10;
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	// and now the fill
+	{
+		uiDrawBrushGradientStop stops[2];
+
+		stops[0].Pos = 0.0;
+		stops[0].R = 0.0;
+		stops[0].G = 1.0;
+		stops[0].B = 1.0;
+		stops[0].A = 0.25;
+		stops[1].Pos = 1.0;
+		stops[1].R = 0.0;
+		stops[1].G = 0.0;
+		stops[1].B = 1.0;
+		stops[1].A = 1.0;
+		brush.Type = uiDrawBrushTypeLinearGradient;
+		brush.X0 = 100 + XO;
+		brush.Y0 = 0 + YO;
+		brush.X1 = 100 + XO;
+		brush.Y1 = 200 + YO;
+		brush.Stops = stops;
+		brush.NumStops = 2;
+		uiDrawFill(p->Context, path, &brush);
+	}
+#undef YO
+#undef XO
+	uiDrawFreePath(path);
+
+	// based on https://msdn.microsoft.com/en-us/library/windows/desktop/dd756679%28v=vs.85%29.aspx
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 585, 235);
+	uiDrawPathArcTo(path,
+		510, 235,
+		75,
+		0,
+		// TODO why doesn't 360° work
+		2 * M_PI - 0.1);
+	uiDrawPathEnd(path);
+	// first the stroke
+	brush.Type = uiDrawBrushTypeSolid;
+	brush.R = 0;
+	brush.G = 0;
+	brush.B = 0;
+	brush.A = 1;
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.MiterLimit = uiDrawDefaultMiterLimit;
+	sp.Thickness = 1;
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	// then the fill
+	{
+		uiDrawBrushGradientStop stops[2];
+
+		stops[0].Pos = 0.0;
+		stops[0].R = 1.0;
+		stops[0].G = 1.0;
+		stops[0].B = 0.0;
+		stops[0].A = 1.0;
+		stops[1].Pos = 1.0;
+		stops[1].R = ((double) 0x22) / 255.0;
+		stops[1].G = ((double) 0x8B) / 255.0;
+		stops[1].B = ((double) 0x22) / 255.0;
+		stops[1].A = 1.0;
+		brush.Type = uiDrawBrushTypeRadialGradient;
+		// start point
+		brush.X0 = 510;
+		brush.Y0 = 235;
+		// outer circle's center
+		brush.X1 = 510;
+		brush.Y1 = 235;
+		brush.OuterRadius = 75;
+		brush.Stops = stops;
+		brush.NumStops = 2;
+		uiDrawFill(p->Context, path, &brush);
+	}
+	uiDrawFreePath(path);
 }
 
 static uintmax_t handlerHScrollMax(uiAreaHandler *a, uiArea *area)

gtkarea/ui.h

@@ -36,14 +36,26 @@ struct uiAreaDrawParams {
 	intmax_t VScrollPos;
 };
 
-// TODO proper sources
 // TODO dotting/dashing
 
+typedef struct uiDrawPath uiDrawPath;
+typedef struct uiDrawBrush uiDrawBrush;
 typedef struct uiDrawStrokeParams uiDrawStrokeParams;
+
+typedef enum uiDrawBrushType uiDrawBrushType;
+typedef struct uiDrawBrushGradientStop uiDrawBrushGradientStop;
+
 typedef enum uiDrawLineCap uiDrawLineCap;
 typedef enum uiDrawLineJoin uiDrawLineJoin;
 typedef enum uiDrawFillMode uiDrawFillMode;
 
+enum uiDrawBrushType {
+	uiDrawBrushTypeSolid,
+	uiDrawBrushTypeLinearGradient,
+	uiDrawBrushTypeRadialGradient,
+	uiDrawBrushTypeImage,
+};
+
 enum uiDrawLineCap {
 	uiDrawLineCapFlat,
 	uiDrawLineCapRound,
@@ -66,28 +78,69 @@ enum uiDrawFillMode {
 	uiDrawFillModeAlternate,
 };
 
+struct uiDrawBrush {
+	uiDrawBrushType Type;
+
+	// solid brushes
+	double R;
+	double G;
+	double B;
+	double A;
+
+	// gradient brushes
+	double X0;		// linear: start X, radial: start X
+	double Y0;		// linear: start Y, radial: start Y
+	double X1;		// linear: end X, radial: outer circle center X
+	double Y1;		// linear: end Y, radial: outer circle center Y
+	double OuterRadius;		// radial gradients only
+	uiDrawBrushGradientStop *Stops;
+	size_t NumStops;
+	// TODO extend mode
+	// cairo: none, repeat, reflect, pad; no individual control
+	// Direct2D: repeat, reflect, pad; no individual control
+	// Core Graphics: none, pad; before and after individually
+	// TODO cairo documentation is inconsistent about pad
+
+	// TODO images
+
+	// TODO transforms
+};
+
+struct uiDrawBrushGradientStop {
+	double Pos;
+	double R;
+	double G;
+	double B;
+	double A;
+};
+
 struct uiDrawStrokeParams {
 	uiDrawLineCap Cap;
 	uiDrawLineJoin Join;
-	intmax_t Thickness;
+	double Thickness;
 	double MiterLimit;
 };
 
-void uiDrawBeginPathRGB(uiDrawContext *, uint8_t, uint8_t, uint8_t);
+uiDrawPath *uiDrawNewPath(uiDrawFillMode);
-// TODO verify these aren't alpha premultiplied anywhere
+void uiDrawFreePath(uiDrawPath *);
-void uiDrawBeginPathRGBA(uiDrawContext *, uint8_t, uint8_t, uint8_t, uint8_t);
 
-void uiDrawMoveTo(uiDrawContext *, intmax_t, intmax_t);
+void uiDrawPathNewFigure(uiDrawPath *, double, double);
-void uiDrawLineTo(uiDrawContext *, intmax_t, intmax_t);
+void uiDrawPathNewFigureWithArc(uiDrawPath *, double, double, double, double, double);
-void uiDrawRectangle(uiDrawContext *, intmax_t, intmax_t, intmax_t, intmax_t);
+void uiDrawPathLineTo(uiDrawPath *, double, double);
 // notes: angles are both relative to 0 and go counterclockwise
-void uiDrawArcTo(uiDrawContext *, intmax_t, intmax_t, intmax_t, double, double, int);
+// TODO is the initial line segment on cairo and OS X a proper join?
-// TODO behavior when there is no initial point on Windows and OS X
+void uiDrawPathArcTo(uiDrawPath *, double, double, double, double, double);
-void uiDrawBezierTo(uiDrawContext *, intmax_t, intmax_t, intmax_t, intmax_t, intmax_t, intmax_t);
+void uiDrawPathBezierTo(uiDrawPath *, double, double, double, double, double, double);
-void uiDrawCloseFigure(uiDrawContext *);
+// TODO quadratic bezier
+void uiDrawPathCloseFigure(uiDrawPath *);
 
-void uiDrawStroke(uiDrawContext *, uiDrawStrokeParams *);
+// TODO effect of these when a figure is already started
-void uiDrawFill(uiDrawContext *, uiDrawFillMode);
+void uiDrawPathAddRectangle(uiDrawPath *, double, double, double, double);
+
+void uiDrawPathEnd(uiDrawPath *);
+
+void uiDrawStroke(uiDrawContext *, uiDrawPath *, uiDrawBrush *, uiDrawStrokeParams *);
+void uiDrawFill(uiDrawContext *, uiDrawPath *, uiDrawBrush *);
 
 // TODO primitives:
 // - rounded rectangles

macarea/alt/main.m

@@ -16,77 +16,216 @@ static struct handler h;
 
 static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *p)
 {
+	uiDrawPath *path;
+	uiDrawBrush brush;
 	uiDrawStrokeParams sp;
 
-	uiDrawBeginPathRGB(p->Context, 0xFF, 0x00, 0x00);
+	brush.Type = uiDrawBrushTypeSolid;
-	uiDrawMoveTo(p->Context, p->ClipX + 5, p->ClipY + 5);
+	brush.A = 1;
-	uiDrawLineTo(p->Context, (p->ClipX + p->ClipWidth) - 5, (p->ClipY + p->ClipHeight) - 5);
+
+	brush.R = 1;
+	brush.G = 0;
+	brush.B = 0;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, p->ClipX + 5, p->ClipY + 5);
+	uiDrawPathLineTo(path, (p->ClipX + p->ClipWidth) - 5, (p->ClipY + p->ClipHeight) - 5);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGB(p->Context, 0x00, 0x00, 0xC0);
+	brush.R = 0;
-	uiDrawMoveTo(p->Context, p->ClipX, p->ClipY);
+	brush.G = 0;
-	uiDrawLineTo(p->Context, p->ClipX + p->ClipWidth, p->ClipY);
+	brush.B = 0.75;
-	uiDrawLineTo(p->Context, 50, 150);
+	path = uiDrawNewPath(uiDrawFillModeWinding);
-	uiDrawLineTo(p->Context, 50, 50);
+	uiDrawPathNewFigure(path, p->ClipX, p->ClipY);
-	uiDrawCloseFigure(p->Context);
+	uiDrawPathLineTo(path, p->ClipX + p->ClipWidth, p->ClipY);
+	uiDrawPathLineTo(path, 50, 150);
+	uiDrawPathLineTo(path, 50, 50);
+	uiDrawPathCloseFigure(path);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinRound;
 	sp.Thickness = 5;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGBA(p->Context, 0x00, 0xC0, 0x00, 0x80);
+	brush.R = 0;
-	uiDrawRectangle(p->Context, 120, 80, 50, 50);
+	brush.G = 0.75;
-	uiDrawFill(p->Context, uiDrawFillModeWinding);
+	brush.B = 0;
+	brush.A = 0.5;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathAddRectangle(path, 120, 80, 50, 50);
+	uiDrawPathEnd(path);
+	uiDrawFill(p->Context, path, &brush);
+	uiDrawFreePath(path);
+	brush.A = 1;
 
-	uiDrawBeginPathRGB(p->Context, 0x00, 0x80, 0x00);
+	brush.R = 0;
-	uiDrawMoveTo(p->Context, 5, 10);
+	brush.G = 0.5;
-	uiDrawLineTo(p->Context, 5, 50);
+	brush.B = 0;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 5.5, 10.5);
+	uiDrawPathLineTo(path, 5.5, 50.5);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGB(p->Context, 0x80, 0xC0, 0x00);
+	brush.R = 0.5;
-	uiDrawMoveTo(p->Context, 400, 100);
+	brush.G = 0.75;
-	uiDrawArcTo(p->Context,
+	brush.B = 0;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 400, 100);
+	uiDrawPathArcTo(path,
 		400, 100,
 		50,
 		30. * (M_PI / 180.),
 		// note the end angle here
 		// in GDI, the second angle to AngleArc() is relative to the start, not to 0
-		330. * (M_PI / 180.),
+		330. * (M_PI / 180.));
-		1);
 	// TODO add a checkbox for this
-	uiDrawLineTo(p->Context, 400, 100);
+	uiDrawPathLineTo(path, 400, 100);
-	uiDrawArcTo(p->Context,
+	uiDrawPathNewFigureWithArc(path,
 		510, 100,
 		50,
 		30. * (M_PI / 180.),
-		330. * (M_PI / 180.),
+		330. * (M_PI / 180.));
-		0);
+	uiDrawPathCloseFigure(path);
-	uiDrawCloseFigure(p->Context);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
 
-	uiDrawBeginPathRGB(p->Context, 0x00, 0x80, 0xC0);
+	brush.R = 0;
-	uiDrawMoveTo(p->Context, 300, 300);
+	brush.G = 0.5;
-	uiDrawBezierTo(p->Context,
+	brush.B = 0.75;
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 300, 300);
+	uiDrawPathBezierTo(path,
 		350, 320,
 		310, 390,
 		435, 372);
+	uiDrawPathEnd(path);
 	sp.Cap = uiDrawLineCapFlat;
 	sp.Join = uiDrawLineJoinMiter;
 	sp.Thickness = 1;
 	sp.MiterLimit = uiDrawDefaultMiterLimit;
-	uiDrawStroke(p->Context, &sp);
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	uiDrawFreePath(path);
+
+	// based on https://msdn.microsoft.com/en-us/library/windows/desktop/dd756682%28v=vs.85%29.aspx
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+#define XO 50
+#define YO 250
+	uiDrawPathNewFigure(path, 0 + XO, 0 + YO);
+	uiDrawPathLineTo(path, 200 + XO, 0 + YO);
+	uiDrawPathBezierTo(path,
+		150 + XO, 50 + YO,
+		150 + XO, 150 + YO,
+		200 + XO, 200 + YO);
+	uiDrawPathLineTo(path, 0 + XO, 200 + YO);
+	uiDrawPathBezierTo(path,
+		50 + XO, 150 + YO,
+		50 + XO, 50 + YO,
+		0 + XO, 0 + YO);
+	uiDrawPathCloseFigure(path);
+	uiDrawPathEnd(path);
+	// first the stroke
+	brush.Type = uiDrawBrushTypeSolid;
+	brush.R = 0;
+	brush.G = 0;
+	brush.B = 0;
+	brush.A = 1;
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.MiterLimit = uiDrawDefaultMiterLimit;
+	sp.Thickness = 10;
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	// and now the fill
+	{
+		uiDrawBrushGradientStop stops[2];
+
+		stops[0].Pos = 0.0;
+		stops[0].R = 0.0;
+		stops[0].G = 1.0;
+		stops[0].B = 1.0;
+		stops[0].A = 0.25;
+		stops[1].Pos = 1.0;
+		stops[1].R = 0.0;
+		stops[1].G = 0.0;
+		stops[1].B = 1.0;
+		stops[1].A = 1.0;
+		brush.Type = uiDrawBrushTypeLinearGradient;
+		brush.X0 = 100 + XO;
+		brush.Y0 = 0 + YO;
+		brush.X1 = 100 + XO;
+		brush.Y1 = 200 + YO;
+		brush.Stops = stops;
+		brush.NumStops = 2;
+		uiDrawFill(p->Context, path, &brush);
+	}
+#undef YO
+#undef XO
+	uiDrawFreePath(path);
+
+	// based on https://msdn.microsoft.com/en-us/library/windows/desktop/dd756679%28v=vs.85%29.aspx
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 585, 235);
+	uiDrawPathArcTo(path,
+		510, 235,
+		75,
+		0,
+		// TODO why doesn't 360° work
+		2 * M_PI - 0.1);
+	uiDrawPathEnd(path);
+	// first the stroke
+	brush.Type = uiDrawBrushTypeSolid;
+	brush.R = 0;
+	brush.G = 0;
+	brush.B = 0;
+	brush.A = 1;
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.MiterLimit = uiDrawDefaultMiterLimit;
+	sp.Thickness = 1;
+	uiDrawStroke(p->Context, path, &brush, &sp);
+	// then the fill
+	{
+		uiDrawBrushGradientStop stops[2];
+
+		stops[0].Pos = 0.0;
+		stops[0].R = 1.0;
+		stops[0].G = 1.0;
+		stops[0].B = 0.0;
+		stops[0].A = 1.0;
+		stops[1].Pos = 1.0;
+		stops[1].R = ((double) 0x22) / 255.0;
+		stops[1].G = ((double) 0x8B) / 255.0;
+		stops[1].B = ((double) 0x22) / 255.0;
+		stops[1].A = 1.0;
+		brush.Type = uiDrawBrushTypeRadialGradient;
+		// start point
+		brush.X0 = 510;
+		brush.Y0 = 235;
+		// outer circle's center
+		brush.X1 = 510;
+		brush.Y1 = 235;
+		brush.OuterRadius = 75;
+		brush.Stops = stops;
+		brush.NumStops = 2;
+		uiDrawFill(p->Context, path, &brush);
+	}
+	uiDrawFreePath(path);
 }
 
 static uintmax_t handlerHScrollMax(uiAreaHandler *a, uiArea *area)

macarea/alt/ui.h

@@ -36,14 +36,26 @@ struct uiAreaDrawParams {
 	intmax_t VScrollPos;
 };
 
-// TODO proper sources
 // TODO dotting/dashing
 
+typedef struct uiDrawPath uiDrawPath;
+typedef struct uiDrawBrush uiDrawBrush;
 typedef struct uiDrawStrokeParams uiDrawStrokeParams;
+
+typedef enum uiDrawBrushType uiDrawBrushType;
+typedef struct uiDrawBrushGradientStop uiDrawBrushGradientStop;
+
 typedef enum uiDrawLineCap uiDrawLineCap;
 typedef enum uiDrawLineJoin uiDrawLineJoin;
 typedef enum uiDrawFillMode uiDrawFillMode;
 
+enum uiDrawBrushType {
+	uiDrawBrushTypeSolid,
+	uiDrawBrushTypeLinearGradient,
+	uiDrawBrushTypeRadialGradient,
+	uiDrawBrushTypeImage,
+};
+
 enum uiDrawLineCap {
 	uiDrawLineCapFlat,
 	uiDrawLineCapRound,
@@ -66,28 +78,69 @@ enum uiDrawFillMode {
 	uiDrawFillModeAlternate,
 };
 
+struct uiDrawBrush {
+	uiDrawBrushType Type;
+
+	// solid brushes
+	double R;
+	double G;
+	double B;
+	double A;
+
+	// gradient brushes
+	double X0;		// linear: start X, radial: start X
+	double Y0;		// linear: start Y, radial: start Y
+	double X1;		// linear: end X, radial: outer circle center X
+	double Y1;		// linear: end Y, radial: outer circle center Y
+	double OuterRadius;		// radial gradients only
+	uiDrawBrushGradientStop *Stops;
+	size_t NumStops;
+	// TODO extend mode
+	// cairo: none, repeat, reflect, pad; no individual control
+	// Direct2D: repeat, reflect, pad; no individual control
+	// Core Graphics: none, pad; before and after individually
+	// TODO cairo documentation is inconsistent about pad
+
+	// TODO images
+
+	// TODO transforms
+};
+
+struct uiDrawBrushGradientStop {
+	double Pos;
+	double R;
+	double G;
+	double B;
+	double A;
+};
+
 struct uiDrawStrokeParams {
 	uiDrawLineCap Cap;
 	uiDrawLineJoin Join;
-	intmax_t Thickness;
+	double Thickness;
 	double MiterLimit;
 };
 
-void uiDrawBeginPathRGB(uiDrawContext *, uint8_t, uint8_t, uint8_t);
+uiDrawPath *uiDrawNewPath(uiDrawFillMode);
-// TODO verify these aren't alpha premultiplied anywhere
+void uiDrawFreePath(uiDrawPath *);
-void uiDrawBeginPathRGBA(uiDrawContext *, uint8_t, uint8_t, uint8_t, uint8_t);
 
-void uiDrawMoveTo(uiDrawContext *, intmax_t, intmax_t);
+void uiDrawPathNewFigure(uiDrawPath *, double, double);
-void uiDrawLineTo(uiDrawContext *, intmax_t, intmax_t);
+void uiDrawPathNewFigureWithArc(uiDrawPath *, double, double, double, double, double);
-void uiDrawRectangle(uiDrawContext *, intmax_t, intmax_t, intmax_t, intmax_t);
+void uiDrawPathLineTo(uiDrawPath *, double, double);
 // notes: angles are both relative to 0 and go counterclockwise
-void uiDrawArcTo(uiDrawContext *, intmax_t, intmax_t, intmax_t, double, double, int);
+// TODO is the initial line segment on cairo and OS X a proper join?
-// TODO behavior when there is no initial point on Windows and OS X
+void uiDrawPathArcTo(uiDrawPath *, double, double, double, double, double);
-void uiDrawBezierTo(uiDrawContext *, intmax_t, intmax_t, intmax_t, intmax_t, intmax_t, intmax_t);
+void uiDrawPathBezierTo(uiDrawPath *, double, double, double, double, double, double);
-void uiDrawCloseFigure(uiDrawContext *);
+// TODO quadratic bezier
+void uiDrawPathCloseFigure(uiDrawPath *);
 
-void uiDrawStroke(uiDrawContext *, uiDrawStrokeParams *);
+// TODO effect of these when a figure is already started
-void uiDrawFill(uiDrawContext *, uiDrawFillMode);
+void uiDrawPathAddRectangle(uiDrawPath *, double, double, double, double);
+
+void uiDrawPathEnd(uiDrawPath *);
+
+void uiDrawStroke(uiDrawContext *, uiDrawPath *, uiDrawBrush *, uiDrawStrokeParams *);
+void uiDrawFill(uiDrawContext *, uiDrawPath *, uiDrawBrush *);
 
 // TODO primitives:
 // - rounded rectangles