From cc827919b8b997e32d97e6b72cc1d7964789f283 Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Tue, 13 Oct 2015 11:16:06 -0400
Subject: [PATCH] Added uiDrawClip() and implemented it on GTK+.

---
 test/drawtests.c | 42 +++++++++++++++++++++++++++++++++++++++++-
 ui.h             |  3 ++-
 unix/draw.c      | 14 ++++++++++++++
 3 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/test/drawtests.c b/test/drawtests.c
index f601a24b..07f6f404 100644
--- a/test/drawtests.c
+++ b/test/drawtests.c
@@ -1299,7 +1299,46 @@ static void drawCSArcNegative(uiAreaDrawParams *p)
 	uiDrawFreePath(path);
 }
 
-// TODO clip
+// clip
+static void drawCSClip(uiAreaDrawParams *p)
+{
+	uiDrawBrush source;
+	uiDrawStrokeParams sp;
+	uiDrawPath *path;
+
+	crsourcergba(&source, 0, 0, 0, 1);
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.MiterLimit = uiDrawDefaultMiterLimit;
+
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+
+	uiDrawPathNewFigureWithArc(path,
+		128.0, 128.0,
+		76.8,
+		0, 2 * M_PI,
+		0);
+	uiDrawPathEnd(path);
+	uiDrawClip(p->Context, path);
+	uiDrawFreePath(path);
+
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathAddRectangle(path, 0, 0, 256, 256);
+	uiDrawPathEnd(path);
+	uiDrawFill(p->Context, path, &source);
+	uiDrawFreePath(path);
+
+	crsourcergba(&source, 0, 1, 0, 1);
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathNewFigure(path, 0, 0);
+	uiDrawPathLineTo(path, 256, 256);
+	uiDrawPathNewFigure(path, 256, 0);
+	uiDrawPathLineTo(path, 0, 256);
+	uiDrawPathEnd(path);
+	sp.Thickness = 10.0;
+	uiDrawStroke(p->Context, path, &source, &sp);
+	uiDrawFreePath(path);
+}
 
 // TODO clip image
 
@@ -1772,6 +1811,7 @@ static const struct drawtest tests[] = {
 	{ "Direct2D: How to Draw and Fill a Complex Shape", drawD2DComplexShape },
 	{ "cairo samples: arc", drawCSArc },
 	{ "cairo samples: arc negative", drawCSArcNegative },
+	{ "cairo samples: clip", drawCSClip },
 	{ "cairo samples: curve rectangle", drawCSCurveRectangle },
 	{ "cairo samples: curve to", drawCSCurveTo },
 	{ "cairo samples: fill and stroke2", drawCSFillAndStroke2 },
diff --git a/ui.h b/ui.h
index 2c4916e2..9cebd73d 100644
--- a/ui.h
+++ b/ui.h
@@ -425,7 +425,8 @@ _UI_EXTERN void uiDrawMatrixTransformSize(uiDrawMatrix *m, double *x, double *y)
 
 _UI_EXTERN void uiDrawTransform(uiDrawContext *c, uiDrawMatrix *m);
 
-// TODO put uiDrawClip here
+// TODO add a uiDrawPathStrokeToFill() or something like that
+_UI_EXTERN void uiDrawClip(uiDrawContext *c, uiDrawPath *path);
 
 _UI_EXTERN void uiDrawSave(uiDrawContext *c);
 _UI_EXTERN void uiDrawRestore(uiDrawContext *c);
diff --git a/unix/draw.c b/unix/draw.c
index 677b1ccd..5cf1e546 100644
--- a/unix/draw.c
+++ b/unix/draw.c
@@ -422,6 +422,20 @@ void uiDrawTransform(uiDrawContext *c, uiDrawMatrix *m)
 	cairo_transform(c->cr, &cm);
 }
 
+void uiDrawClip(uiDrawContext *c, uiDrawPath *path)
+{
+	runPath(path, c->cr);
+	switch (path->fillMode) {
+	case uiDrawFillModeWinding:
+		cairo_set_fill_rule(c->cr, CAIRO_FILL_RULE_WINDING);
+		break;
+	case uiDrawFillModeAlternate:
+		cairo_set_fill_rule(c->cr, CAIRO_FILL_RULE_EVEN_ODD);
+		break;
+	}
+	cairo_clip(c->cr);
+}
+
 void uiDrawSave(uiDrawContext *c)
 {
 	cairo_save(c->cr);