karma/flying-balls
1
1
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

drawing using cairo

Browse Source
This commit is contained in:
Antonio Carzaniga 2019-07-28 14:55:39 +02:00
parent ea1db822ba
commit e306fffc2a
1 changed files with 40 additions and 83 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

123
balls.c
View File

@ -22,10 +22,10 @@ struct ball {
guchar rgb_channels[3]; guchar rgb_channels[3];
}; };
static double delta = 0.01; static double delta = 0.01; /* seconds */
static unsigned int width = 0; static unsigned int width = DEFAULT_WIDTH;
static unsigned int height = 0; static unsigned int height = DEFAULT_HEIGHT;
static unsigned int radius_min = 5; static unsigned int radius_min = 5;
static unsigned int radius_max = 10; 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 () { static void update_state () {
for(int i = 0; i < n_balls; ++i) for(int i = 0; i < n_balls; ++i)
for(int j = i + 1; j < n_balls; ++j) for(int j = i + 1; j < n_balls; ++j)
@ -168,53 +136,40 @@ static void update_state () {
} }
static GtkWidget * window; static GtkWidget * window;
static cairo_t * cr = 0;
static void draw_balls_onto_pixbuf () { static void draw_balls_onto_window () {
guchar * const pixels = gdk_pixbuf_get_pixels(pixbuf); if (!cr)
int width = gdk_pixbuf_get_width(pixbuf); cr = gdk_cairo_create(window->window);
int height = gdk_pixbuf_get_height(pixbuf);
int row_stride = gdk_pixbuf_get_rowstride(pixbuf);
int n_channels = gdk_pixbuf_get_n_channels(pixbuf);
/* clear pixmap */ /* clear pixmap */
for(int y = 0; y < height; ++y) { cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
unsigned char * px = pixels + y*row_stride; cairo_paint(cr);
for(int x = 0; x < width; ++x) {
for(int i = 0; i < n_channels; ++i)
*px++ *= clear_factor[i];
}
}
/* draw balls */ /* draw balls */
for(int i = 0; i < n_balls; ++i) { for(int i = 0; i < n_balls; ++i) {
int x0 = balls[i].x <= balls[i].radius ? 0 : balls[i].x - balls[i].radius; cairo_set_source_rgb(cr,
int x1 = balls[i].x + balls[i].radius + 1 >= width ? width : balls[i].x + balls[i].radius + 1; 1.0*balls[i].rgb_channels[0]/255,
int y0 = balls[i].y <= balls[i].radius ? 0 : balls[i].y - balls[i].radius; 1.0*balls[i].rgb_channels[1]/255,
int y1 = balls[i].y + balls[i].radius + 1 >= height ? height : balls[i].y + balls[i].radius + 1; 1.0*balls[i].rgb_channels[2]/255);
for (int y = y0; y < y1; ++y) { cairo_arc(cr, balls[i].x, balls[i].y, balls[i].radius, 0, 2 * M_PI);
assert(y >= 0); cairo_fill(cr);
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;
}
}
} }
} }
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) if (width == widget->allocation.width && height == widget->allocation.height)
return FALSE; return FALSE;
create_surface(widget->allocation.width, widget->allocation.height); width = widget->allocation.width;
draw_balls_onto_pixbuf(); height = widget->allocation.height;
gdk_draw_pixbuf(window->window, NULL, pixbuf,
0, 0, 0, 0, width, height, if (cr) {
GDK_RGB_DITHER_NONE, 0, 0); cairo_destroy(cr);
cr = gdk_cairo_create(window->window);
}
draw_balls_onto_window();
return TRUE; return TRUE;
} }
@ -233,19 +188,28 @@ static gint keyboard_input (GtkWidget *widget, GdkEventKey *event) {
} }
static gboolean expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer data) { 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; return TRUE;
} }
static void destroy_window (void) { static void destroy_window (void) {
gtk_main_quit(); gtk_main_quit();
if (cr) {
cairo_destroy(cr);
cr = 0;
}
} }
void print_usage (const char * progname) { void print_usage (const char * progname) {
fprintf(stderr, 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); progname);
} }
@ -253,10 +217,7 @@ gboolean timeout (gpointer user_data) {
guint64 start = g_get_monotonic_time (); guint64 start = g_get_monotonic_time ();
update_state(); update_state();
draw_balls_onto_pixbuf(); draw_balls_onto_window();
gdk_draw_pixbuf(window->window, NULL, pixbuf,
0, 0, 0, 0, width, height,
GDK_RGB_DITHER_NONE, 0, 0);
guint64 elapsed_usec = g_get_monotonic_time () - start; guint64 elapsed_usec = g_get_monotonic_time () - start;
@ -282,8 +243,6 @@ int main (int argc, const char *argv[]) {
continue; continue;
if (sscanf(argv[i], "n=%u", &n_balls) == 1) if (sscanf(argv[i], "n=%u", &n_balls) == 1)
continue; 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) if (sscanf(argv[i], "fx=%lf", &g_x) == 1)
continue; continue;
if (sscanf(argv[i], "fy=%lf", &g_y) == 1) 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); balls = malloc(sizeof(struct ball)*n_balls);
assert(balls); assert(balls);
create_surface(w, h);
balls_init_state(); balls_init_state();
gtk_init(0, 0); 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, "destroy", G_CALLBACK(destroy_window), NULL);
g_signal_connect(window, "expose-event", G_CALLBACK(expose_event), 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); 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); 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); free(balls);
destroy_surface();
return 0; return 0;
} }