Add some rudimentary clipping variations

7 files changed, 148 insertions, 7 deletions

diff --git a/chart-demo.c b/chart-demo.c
index 0c76fe1..488a922 100644
--- a/chart-demo.c
+++ b/chart-demo.c
@@ -185,12 +185,14 @@ int main (int argc, char **argv)
 	int show_fps = 1;
 	int benchmark;
 	cairo_antialias_t antialias;
+	enum clip clip;
 
 	struct chart c[5];
 	int n;
 
 	device = device_open(argc, argv);
 	antialias = device_get_antialias(argc, argv);
+	clip = device_get_clip(argc, argv);
 	benchmark = device_get_benchmark(argc, argv);
 	if (benchmark == 0)
 		benchmark = 20;
@@ -214,6 +216,7 @@ int main (int argc, char **argv)
 		cr = cairo_create(fb->surface);
 
 		bg_draw(device, cr);
+		device_apply_clip(device, cr, clip);
 
 		cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
 		for (n = 0; n < 5; n++)
@@ -226,8 +229,10 @@ int main (int argc, char **argv)
 			chart_stroke(device, cr, &c[n]);
 
 		gettimeofday(&now, NULL);
-		if (show_fps && last_fps.tv_sec)
+		if (show_fps && last_fps.tv_sec) {
+			cairo_reset_clip (cr);
 			fps_draw(cr, device->name, &last_fps, &now);
+		}
 		last_fps = now;
 
 		cairo_destroy(cr);
diff --git a/demo.c b/demo.c
index 86c2551..733461b 100644
--- a/demo.c
+++ b/demo.c
@@ -1,6 +1,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <math.h>
 
 #include "demo.h"
 
@@ -275,3 +276,86 @@ fps_draw (cairo_t *cr, const char *name,
     cairo_show_text (cr, buf);
 }
 
+#ifndef min
+#define min(a, b) ((a) <= (b) ? (a) : (b))
+#endif
+
+enum clip device_get_clip(int argc, char **argv)
+{
+	const char *clip = NULL;
+	enum clip c;
+	int n;
+
+	for (n = 1; n < argc; n++) {
+		if (strcmp (argv[n], "--clip") == 0 && n < argc - 1)
+			clip = argv[++n];
+		else if (strncmp (argv[n], "--clip=", 7) == 0)
+			clip = argv[n] + 7;
+	}
+
+	c = CLIP_NONE;
+	if (clip) {
+		if (strcmp (clip, "none") == 0) {
+		} else if (strcmp (clip, "region") == 0 || strcmp (clip, "region1") == 0) {
+			c = CLIP_REGION1;
+		} else if (strcmp (clip, "box") == 0 || strcmp (clip, "box1") == 0) {
+			c = CLIP_BOX1;
+		} else if (strcmp (clip, "region2") == 0) {
+			c = CLIP_REGION2;
+		} else if (strcmp (clip, "box2") == 0) {
+			c = CLIP_BOX2;
+		} else if (strcmp (clip, "diamond") == 0) {
+			c = CLIP_DIAMOND;
+		} else if (strcmp (clip, "circle") == 0) {
+			c = CLIP_CIRCLE;
+		}
+	}
+
+	return c;
+}
+
+void device_apply_clip(struct device *device, cairo_t *cr, enum clip c)
+{
+	cairo_new_path (cr);
+	switch (c) {
+	case CLIP_NONE:
+		return;
+	case CLIP_REGION1:
+		cairo_rectangle (cr,
+				 device->width/4, device->height/4,
+				 device->width/2, device->height/2);
+		break;
+	case CLIP_BOX1:
+		cairo_rectangle (cr,
+				 device->width/4+.25, device->height/4+.25,
+				 device->width/2, device->height/2);
+		break;
+	case CLIP_REGION2:
+		cairo_rectangle (cr,
+				 0, 0, 3*device->width/4, 3*device->height/4);
+		cairo_rectangle (cr,
+				 device->width/4, device->height/4,
+				 3*device->width/4, 3*device->height/4);
+		break;
+	case CLIP_BOX2:
+		cairo_rectangle (cr,
+				 0.25, 0.25, 3*device->width/4, 3*device->height/4);
+		cairo_rectangle (cr,
+				 device->width/4-.25, device->height/4-.25,
+				 3*device->width/4 + .25, 3*device->height/4 + .25);
+		break;
+	case CLIP_DIAMOND:
+		cairo_move_to (cr, device->width/2, 0);
+		cairo_line_to (cr, device->width, device->height/2);
+		cairo_line_to (cr, device->width/2, device->height);
+		cairo_line_to (cr, 0, device->height/2);
+		cairo_close_path (cr);
+		break;
+	case CLIP_CIRCLE:
+		cairo_arc (cr, device->width/2, device->height/2,
+			   min(device->width/2, device->height/2),
+			   0, 2 * M_PI);
+		break;
+	}
+	cairo_clip (cr);
+}
diff --git a/demo.h b/demo.h
index ddfca9f..8415be8 100644
--- a/demo.h
+++ b/demo.h
@@ -31,6 +31,16 @@ struct device *device_open(int argc, char **argv);
 int device_get_size(int argc, char **argv, int *width, int *height);
 cairo_antialias_t device_get_antialias(int argc, char **argv);
 int device_get_benchmark(int argc, char **argv);
+enum clip {
+	CLIP_NONE,
+	CLIP_REGION1,
+	CLIP_BOX1,
+	CLIP_REGION2,
+	CLIP_BOX2,
+	CLIP_DIAMOND,
+	CLIP_CIRCLE,
+} device_get_clip(int argc, char **argv);
+void device_apply_clip(struct device *device, cairo_t *cr, enum clip c);
 
 #if HAVE_COGL
 struct device *cogl_open (int argc, char **argv);
diff --git a/fish-demo.c b/fish-demo.c
index 358a385..413977b 100644
--- a/fish-demo.c
+++ b/fish-demo.c
@@ -172,10 +172,12 @@ int main (int argc, char **argv)
 	int frame = 0;
 	int frames = 0;
 	int benchmark;
+	enum clip clip;
 	cairo_pattern_t *reflection = NULL;
 	int x1, x2;
 
 	device = device_open(argc, argv);
+	clip = device_get_clip(argc, argv);
 	benchmark = device_get_benchmark(argc, argv);
 	if (benchmark == 0)
 		benchmark = 20;
@@ -215,6 +217,9 @@ int main (int argc, char **argv)
 		cairo_t *cr;
 
 		cr = cairo_create(fb->surface);
+
+		device_apply_clip(device, cr, clip);
+
 		cairo_set_source(cr, bg);
 		if (reflection)
 			cairo_mask(cr, reflection);
diff --git a/flowers-demo.c b/flowers-demo.c
index 9ab07ee..204c2bb 100644
--- a/flowers-demo.c
+++ b/flowers-demo.c
@@ -247,6 +247,7 @@ naive_flowers_draw (cairo_t *cr, bool opaque)
 	cairo_matrix_t m;
 
 	if (! opaque) {
+		cairo_save (cr);
 		cairo_rectangle (cr, 0, 0, f->size, f->size);
 		cairo_clip (cr);
 		cairo_push_group (cr);
@@ -318,12 +319,13 @@ naive_flowers_draw (cairo_t *cr, bool opaque)
 		cairo_stroke (cr);
 	}
 	if (! opaque) {
-		cairo_pop_group_to_source(cr);
-		cairo_reset_clip (cr);
-
+		cairo_pattern_t *p = cairo_pop_group(cr);
+		cairo_restore (cr);
 		cairo_matrix_init_translate (&m, -f->x, -f->y);
-		cairo_pattern_set_matrix (cairo_get_source(cr), &m);
+		cairo_pattern_set_matrix (p, &m);
+		cairo_set_source (cr, p);
 		cairo_paint_with_alpha (cr, f->fade);
+		cairo_pattern_destroy (p);
 	} else
 		cairo_restore (cr);
     }
@@ -356,11 +358,13 @@ int main (int argc, char **argv)
 	int frame = 0;
 	int frames = 0;
 	int benchmark;
+	enum clip clip;
 	void (*draw) (cairo_t *, bool);
 	int naive, opaque;
 	int i;
 
 	device = device_open(argc, argv);
+	clip = device_get_clip(argc, argv);
 	benchmark = device_get_benchmark(argc, argv);
 	if (benchmark == 0)
 		benchmark = 20;
@@ -392,6 +396,7 @@ int main (int argc, char **argv)
 		cairo_paint (cr);
 		cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
 
+		device_apply_clip (device, cr, clip);
 		draw(cr, opaque);
 
 		gettimeofday(&now, NULL);
diff --git a/glx.c b/glx.c
index e1fa4d5..a8668fe 100644
--- a/glx.c
+++ b/glx.c
@@ -3,6 +3,7 @@
 #include "demo.h"
 
 #include <stdlib.h>
+#include <string.h>
 #include <X11/X.h>
 
 struct glx_device {
@@ -13,6 +14,8 @@ struct glx_device {
     Window drawable;
     GLXContext ctx;
     cairo_device_t *device;
+
+    int double_buffered;
 };
 
 static void
@@ -23,7 +26,16 @@ destroy (struct framebuffer *fb)
 static void
 show (struct framebuffer *fb)
 {
-    cairo_gl_surface_swapbuffers (fb->surface);
+    struct glx_device *device = (struct glx_device *) fb->device;
+
+    if (device->double_buffered) {
+	cairo_t *cr = cairo_create (device->base.scanout);
+	cairo_set_source_surface (cr, fb->surface, 0, 0);
+	cairo_paint (cr);
+	cairo_destroy (cr);
+    }
+
+    cairo_gl_surface_swapbuffers (device->base.scanout);
 }
 
 static struct framebuffer *
@@ -51,6 +63,7 @@ glx_open (int argc, char **argv)
 	Screen *scr;
 	int screen;
 	XSetWindowAttributes attr;
+	int i;
 
 	dpy = XOpenDisplay (NULL);
 	if (dpy == NULL)
@@ -65,6 +78,13 @@ glx_open (int argc, char **argv)
 	device->fb.show = show;
 	device->fb.destroy = destroy;
 
+	device->double_buffered = 0;
+	for (i = 1; i < argc; i++) {
+		if (strcmp (argv[i], "--double") == 0)
+			device->double_buffered = 1;
+	}
+
+
 	screen = DefaultScreen (dpy);
 	scr = XScreenOfDisplay (dpy, screen);
 	device->base.width = WidthOfScreen (scr);
@@ -104,7 +124,14 @@ glx_open (int argc, char **argv)
 						    device->drawable,
 						    device->base.width,
 						    device->base.height);
+    if (device->double_buffered) {
+	device->fb.surface = cairo_surface_create_similar (device->base.scanout,
+							   CAIRO_CONTENT_COLOR,
+							   device->base.width,
+							   device->base.height);
+    } else {
 	device->fb.surface = device->base.scanout;
+    }
 
 	return &device->base;
 }
diff --git a/tiger-demo.c b/tiger-demo.c
index 0712a8f..136351d 100644
--- a/tiger-demo.c
+++ b/tiger-demo.c
@@ -24,6 +24,7 @@
 static void tiger(struct device *device,
 		  struct framebuffer *fb,
 		  cairo_antialias_t antialias,
+		  enum clip c,
 		  double scale,
 		  double rotation)
 {
@@ -39,6 +40,8 @@ static void tiger(struct device *device,
 	cairo_paint (cr);
 	cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
 
+	device_apply_clip (device, cr, c);
+
 	cairo_translate (cr, device->width/2, device->height/2);
 	cairo_translate (cr, 32, 30);
 	cairo_scale (cr, scale, scale);
@@ -77,6 +80,7 @@ int main (int argc, char **argv)
 	struct timeval start, last_tty, last_fps, now;
 
 	cairo_antialias_t antialias;
+	enum clip clip;
 
 	double scale = 0.1;
 	double factor = 1.05;
@@ -89,6 +93,7 @@ int main (int argc, char **argv)
 
 	device = device_open(argc, argv);
 	antialias = device_get_antialias(argc, argv);
+	clip = device_get_clip(argc, argv);
 	benchmark = device_get_benchmark(argc, argv);
 	if (benchmark == 0)
 		benchmark = 20;
@@ -97,7 +102,7 @@ int main (int argc, char **argv)
 	do {
 		struct framebuffer *fb = device->get_framebuffer (device);
 
-		tiger (device, fb, antialias, scale, rotation);
+		tiger (device, fb, antialias, clip, scale, rotation);
 
 		gettimeofday(&now, NULL);
 		if (benchmark < 0 && last_fps.tv_sec) {