add another cairo demo

Makefile

@@ -36,7 +36,7 @@ LOCAL_LIBS = $(patsubst %.c,%.o,$(wildcard ../userspace/lib/*.c))
 LOCAL_INC  = -I ../userspace/
 
 TARGETDIR = ../hdd/bin/
-EXTRA_LIB_APPS = compositor2 cairo-demo pixman-demo
+EXTRA_LIB_APPS = compositor2 cairo-demo pixman-demo make-it-snow
 EXTRA_LIB_TARGETS = $(EXTRA_LIB_APPS:%=$(TARGETDIR)%)
 
 .PHONY: all clean

make-it-snow.c

@@ -0,0 +1,203 @@
+/*
+ * Based on the Wayland/Weston drag and drop demo:
+ * Copyright © 2010 Kristian Høgsberg
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+
+#include <math.h>
+#include <stdio.h>
+#include <cairo.h>
+
+#include "lib/window.h"
+#include "lib/graphics.h"
+#include "lib/list.h"
+
+window_t * window;
+gfx_context_t * ctx;
+list_t * snowflakes;
+
+int width, height;
+
+struct snowflake {
+	int x;
+	int y;
+	cairo_surface_t * surface;
+};
+
+#define random rand
+#define item_width 64
+#define item_height 64
+
+int windspeed = 2;
+int gravity   = 5;
+
+struct snowflake * create_snowflake() {
+
+	struct snowflake * item = malloc(sizeof(struct snowflake));
+
+	item->x = random() % width;
+	item->y = random() % height;
+
+	const int petal_count = 3 + random() % 5;
+	const double r1 = 20 + random() % 10;
+	const double r2 = 5 + random() % 12;
+	const double u = (10 + random() % 90) / 100.0;
+	const double v = (random() % 90) / 100.0;
+
+	cairo_t *cr;
+	int i;
+	double t, dt = 2 * M_PI / (petal_count * 2);
+	double x1, y1, x2, y2, x3, y3;
+
+	item->surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, item_width, item_height);
+
+	cr = cairo_create(item->surface);
+	cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
+	cairo_set_source_rgba(cr, 0, 0, 0, 0);
+	cairo_paint(cr);
+
+	cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
+	cairo_translate(cr, item_width / 2, item_height / 2);
+	t = random();
+	cairo_move_to(cr, cos(t) * r1, sin(t) * r1);
+	for (i = 0; i < petal_count; i++, t += dt * 2) {
+		x1 = cos(t) * r1;
+		y1 = sin(t) * r1;
+		x2 = cos(t + dt) * r2;
+		y2 = sin(t + dt) * r2;
+		x3 = cos(t + 2 * dt) * r1;
+		y3 = sin(t + 2 * dt) * r1;
+
+		cairo_curve_to(cr,
+			       x1 - y1 * u, y1 + x1 * u,
+			       x2 + y2 * v, y2 - x2 * v,
+			       x2, y2);
+
+		cairo_curve_to(cr,
+			       x2 - y2 * v, y2 + x2 * v,
+			       x3 + y3 * u, y3 - x3 * u,
+			       x3, y3);
+	}
+
+	cairo_close_path(cr);
+
+	cairo_set_source_rgba(cr,
+			      0.5 + (random() % 50) / 49.0,
+			      0.5 + (random() % 50) / 49.0,
+			      0.5 + (random() % 50) / 49.0,
+			      0.5 + (random() % 100) / 99.0);
+
+	cairo_fill_preserve(cr);
+
+	cairo_set_line_width(cr, 1);
+	cairo_set_source_rgba(cr,
+			      0.5 + (random() % 50) / 49.0,
+			      0.5 + (random() % 50) / 49.0,
+			      0.5 + (random() % 50) / 49.0,
+			      0.5 + (random() % 100) / 99.0);
+	cairo_stroke(cr);
+
+	cairo_destroy(cr);;
+
+	return item;
+}
+
+void render() {
+	/* Clear window */
+	draw_fill(ctx, rgba(0,0,0,0));
+
+	/* Set up cairo context */
+	int stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, window->width);
+	cairo_surface_t * surface = cairo_image_surface_create_for_data(ctx->backbuffer, CAIRO_FORMAT_ARGB32, window->width, window->height, stride);
+	cairo_t * cr = cairo_create(surface);
+
+	/* Draw some snowflakes */
+	foreach(node, snowflakes) {
+		struct snowflake * item = node->value;
+		cairo_save(cr);
+
+		cairo_set_source_surface(cr, item->surface, item->x, item->y);
+		cairo_paint(cr);
+
+		item->x += windspeed;
+		item->y += gravity;
+
+		if (item->y > height + item_height) {
+			item->y = -item_height;
+		}
+		if (item->x > width + item_width) {
+			item->x = -item_width;
+		}
+
+		cairo_restore(cr);
+	}
+
+	cairo_surface_flush(surface);
+	cairo_destroy(cr);
+	cairo_surface_flush(surface);
+	cairo_surface_destroy(surface);
+
+	flip(ctx);
+}
+
+void resize_callback(window_t * win) {
+	reinit_graphics_window(ctx, window);
+	render();
+}
+
+
+int main(int argc, char * argv[]) {
+	setup_windowing();
+
+	resize_window_callback = resize_callback;
+
+	width  = wins_globals->server_width;
+	height = wins_globals->server_height;
+
+	window = window_create(0,0,width,height);
+	ctx = init_graphics_window_double_buffer(window);
+	draw_fill(ctx, rgba(0,0,0,0));
+	flip(ctx);
+	window_enable_alpha(window);
+
+	snowflakes = list_create();
+	for (int i = 0; i < 100; ++i) {
+		list_insert(snowflakes, create_snowflake());
+	}
+
+	render();
+
+	while (1) {
+		w_keyboard_t * kbd = poll_keyboard();
+		if (kbd != NULL) {
+			if (kbd->key == 'q') {
+				break;
+			}
+			free(kbd);
+		}
+		render();
+	}
+
+
+	teardown_windowing();
+
+	return 0;
+}