drawing using cairo
This commit is contained in:
Antonio Carzaniga
parent
ea1db822ba
commit
e306fffc2a
123
balls.c
123
balls.c
@ -22,10 +22,10 @@ struct ball {
|
||||
guchar rgb_channels[3];
|
||||
};
|
||||
|
||||
static double delta = 0.01;
|
||||
static double delta = 0.01; /* seconds */
|
||||
|
||||
static unsigned int width = 0;
|
||||
static unsigned int height = 0;
|
||||
static unsigned int width = DEFAULT_WIDTH;
|
||||
static unsigned int height = DEFAULT_HEIGHT;
|
||||
|
||||
static unsigned int radius_min = 5;
|
||||
static unsigned int radius_max = 10;
|
||||
@ -126,38 +126,6 @@ static void ball_update_state (struct ball * p) {
|
||||
}
|
||||
}
|
||||
|
||||
static GdkPixbuf * pixbuf = 0;
|
||||
static double clear_factor [3] = { 0.0, 0.0, 0.0 };
|
||||
|
||||
static void destroy_surface () {
|
||||
if (pixbuf)
|
||||
g_object_unref(pixbuf);
|
||||
|
||||
pixbuf = 0;
|
||||
}
|
||||
|
||||
static void create_surface (int w, int h) {
|
||||
destroy_surface();
|
||||
width = w;
|
||||
height = h;
|
||||
|
||||
pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, 0, 8, width, height);
|
||||
assert(pixbuf);
|
||||
|
||||
guchar * pixels = gdk_pixbuf_get_pixels(pixbuf);
|
||||
int row_stride = gdk_pixbuf_get_rowstride(pixbuf);
|
||||
int n_channels = gdk_pixbuf_get_n_channels(pixbuf);
|
||||
|
||||
for(int y = 0; y < height; ++y) {
|
||||
unsigned char * px = pixels;
|
||||
for(int x = 0; x < width; ++x) {
|
||||
for(int i = 0; i < n_channels; ++i)
|
||||
*px++ = 0;
|
||||
}
|
||||
pixels += row_stride;
|
||||
}
|
||||
}
|
||||
|
||||
static void update_state () {
|
||||
for(int i = 0; i < n_balls; ++i)
|
||||
for(int j = i + 1; j < n_balls; ++j)
|
||||
@ -168,53 +136,40 @@ static void update_state () {
|
||||
}
|
||||
|
||||
static GtkWidget * window;
|
||||
static cairo_t * cr = 0;
|
||||
|
||||
static void draw_balls_onto_pixbuf () {
|
||||
guchar * const pixels = gdk_pixbuf_get_pixels(pixbuf);
|
||||
int width = gdk_pixbuf_get_width(pixbuf);
|
||||
int height = gdk_pixbuf_get_height(pixbuf);
|
||||
int row_stride = gdk_pixbuf_get_rowstride(pixbuf);
|
||||
int n_channels = gdk_pixbuf_get_n_channels(pixbuf);
|
||||
static void draw_balls_onto_window () {
|
||||
if (!cr)
|
||||
cr = gdk_cairo_create(window->window);
|
||||
|
||||
/* clear pixmap */
|
||||
for(int y = 0; y < height; ++y) {
|
||||
unsigned char * px = pixels + y*row_stride;
|
||||
for(int x = 0; x < width; ++x) {
|
||||
for(int i = 0; i < n_channels; ++i)
|
||||
*px++ *= clear_factor[i];
|
||||
}
|
||||
}
|
||||
cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
|
||||
cairo_paint(cr);
|
||||
|
||||
/* draw balls */
|
||||
for(int i = 0; i < n_balls; ++i) {
|
||||
int x0 = balls[i].x <= balls[i].radius ? 0 : balls[i].x - balls[i].radius;
|
||||
int x1 = balls[i].x + balls[i].radius + 1 >= width ? width : balls[i].x + balls[i].radius + 1;
|
||||
int y0 = balls[i].y <= balls[i].radius ? 0 : balls[i].y - balls[i].radius;
|
||||
int y1 = balls[i].y + balls[i].radius + 1 >= height ? height : balls[i].y + balls[i].radius + 1;
|
||||
for (int y = y0; y < y1; ++y) {
|
||||
assert(y >= 0);
|
||||
unsigned char * px = pixels + y*row_stride + x0*n_channels;
|
||||
int radius2_dy2 = balls[i].radius*balls[i].radius - (y - balls[i].y)*(y - balls[i].y);
|
||||
for (int x = x0; x < x1; ++x) {
|
||||
if ((x - balls[i].x)*(x - balls[i].x) <= radius2_dy2)
|
||||
for(int c = 0; c < n_channels; ++c)
|
||||
*px++ = balls[i].rgb_channels[c];
|
||||
else
|
||||
px += n_channels;
|
||||
}
|
||||
}
|
||||
cairo_set_source_rgb(cr,
|
||||
1.0*balls[i].rgb_channels[0]/255,
|
||||
1.0*balls[i].rgb_channels[1]/255,
|
||||
1.0*balls[i].rgb_channels[2]/255);
|
||||
cairo_arc(cr, balls[i].x, balls[i].y, balls[i].radius, 0, 2 * M_PI);
|
||||
cairo_fill(cr);
|
||||
}
|
||||
}
|
||||
|
||||
static gint resize_pixbuf (GtkWidget *widget, GdkEventConfigure * event) {
|
||||
static gint resize_event (GtkWidget *widget, GdkEventConfigure * event) {
|
||||
if (width == widget->allocation.width && height == widget->allocation.height)
|
||||
return FALSE;
|
||||
|
||||
create_surface(widget->allocation.width, widget->allocation.height);
|
||||
draw_balls_onto_pixbuf();
|
||||
gdk_draw_pixbuf(window->window, NULL, pixbuf,
|
||||
0, 0, 0, 0, width, height,
|
||||
GDK_RGB_DITHER_NONE, 0, 0);
|
||||
width = widget->allocation.width;
|
||||
height = widget->allocation.height;
|
||||
|
||||
if (cr) {
|
||||
cairo_destroy(cr);
|
||||
cr = gdk_cairo_create(window->window);
|
||||
}
|
||||
|
||||
draw_balls_onto_window();
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
@ -233,19 +188,28 @@ static gint keyboard_input (GtkWidget *widget, GdkEventKey *event) {
|
||||
}
|
||||
|
||||
static gboolean expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer data) {
|
||||
gdk_draw_pixbuf(window->window, NULL, pixbuf,
|
||||
0, 0, 0, 0, width, height,
|
||||
GDK_RGB_DITHER_NONE, 0, 0);
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
static void destroy_window (void) {
|
||||
gtk_main_quit();
|
||||
if (cr) {
|
||||
cairo_destroy(cr);
|
||||
cr = 0;
|
||||
}
|
||||
}
|
||||
|
||||
void print_usage (const char * progname) {
|
||||
fprintf(stderr,
|
||||
"usage: %s [<width>x<height>] [n=<bumber of balls>] [clear=<clear-red>,<clear-green>,<clear-blue>] [fx=<x-force>] [fy=<y-force>] [radius=<min-radius>-<max-radius>] [delta=<frame-delta-time>]\n",
|
||||
"usage: %s [options...]\n"
|
||||
"options:\n"
|
||||
"\t<width>x<height>\n"
|
||||
"\tn=<bumber of balls>\n"
|
||||
"\tfx=<x-force>\n"
|
||||
"\tfy=<y-force>\n"
|
||||
"\tradius=<min-radius>-<max-radius>\n"
|
||||
"\tv=<min-velocity>-<max-velocity>\n"
|
||||
"\tdelta=<frame-delta-time>\n",
|
||||
progname);
|
||||
}
|
||||
|
||||
@ -253,10 +217,7 @@ gboolean timeout (gpointer user_data) {
|
||||
guint64 start = g_get_monotonic_time ();
|
||||
|
||||
update_state();
|
||||
draw_balls_onto_pixbuf();
|
||||
gdk_draw_pixbuf(window->window, NULL, pixbuf,
|
||||
0, 0, 0, 0, width, height,
|
||||
GDK_RGB_DITHER_NONE, 0, 0);
|
||||
draw_balls_onto_window();
|
||||
|
||||
guint64 elapsed_usec = g_get_monotonic_time () - start;
|
||||
|
||||
@ -282,8 +243,6 @@ int main (int argc, const char *argv[]) {
|
||||
continue;
|
||||
if (sscanf(argv[i], "n=%u", &n_balls) == 1)
|
||||
continue;
|
||||
if (sscanf(argv[i], "clear=%lf,%lf,%lf", clear_factor, clear_factor + 1, clear_factor + 2) == 3)
|
||||
continue;
|
||||
if (sscanf(argv[i], "fx=%lf", &g_x) == 1)
|
||||
continue;
|
||||
if (sscanf(argv[i], "fy=%lf", &g_y) == 1)
|
||||
@ -301,7 +260,6 @@ int main (int argc, const char *argv[]) {
|
||||
balls = malloc(sizeof(struct ball)*n_balls);
|
||||
assert(balls);
|
||||
|
||||
create_surface(w, h);
|
||||
balls_init_state();
|
||||
|
||||
gtk_init(0, 0);
|
||||
@ -314,7 +272,7 @@ int main (int argc, const char *argv[]) {
|
||||
|
||||
g_signal_connect(window, "destroy", G_CALLBACK(destroy_window), NULL);
|
||||
g_signal_connect(window, "expose-event", G_CALLBACK(expose_event), NULL);
|
||||
g_signal_connect(window, "configure_event", G_CALLBACK(resize_pixbuf), NULL);
|
||||
g_signal_connect(window, "configure_event", G_CALLBACK(resize_event), NULL);
|
||||
g_signal_connect(window, "key_press_event", G_CALLBACK(keyboard_input), NULL);
|
||||
|
||||
gtk_widget_set_events (window, GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK | GDK_KEY_PRESS_MASK);
|
||||
@ -327,6 +285,5 @@ int main (int argc, const char *argv[]) {
|
||||
|
||||
free(balls);
|
||||
|
||||
destroy_surface();
|
||||
return 0;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user