func XMain(callbacks Callbacks) {
dpy := C.XOpenDisplay(nil)
w := C.XCreateSimpleWindow(dpy, C.XDefaultRootWindow(dpy),
0, 0, 600, 400,
0, 0, 0)
C.XSelectInput(dpy, w, C.StructureNotifyMask|C.SubstructureNotifyMask|C.ExposureMask)
C.XMapWindow(dpy, w)
win := Window{dpy: dpy, xw: w}
visual := C.XDefaultVisual(dpy, 0)
surf := cairo.XlibSurfaceCreate(unsafe.Pointer(dpy), uint64(win.xw), unsafe.Pointer(visual), 10, 10)
for {
var e C.XEvent
C.XNextEvent(dpy, &e)
typ := XEventType(*(*C.int)(unsafe.Pointer(&e)))
// log.Printf("X event: %s", typ)
switch typ {
case C.ConfigureNotify:
e := (*C.XConfigureEvent)(unsafe.Pointer(&e))
surf.SetSize(int(e.width), int(e.height))
case C.Expose:
cr := cairo.Create(surf.Surface)
callbacks.Draw(cr, surf)
default:
// log.Printf("unknown X event %s", typ)
}
}
}
func main() {
surf := cairo.ImageSurfaceCreate(cairo.FormatRGB24, 640, 480)
cr := cairo.Create(surf.Surface)
cr.Arc(320, 240, 40, 0, math.Pi)
path := cr.CopyPath()
iter := path.Iter()
for seg := iter.Next(); seg != nil; seg = iter.Next() {
log.Printf("seg %s %#v", seg.Type, seg)
}
}
func main() {
size := 320
margin := 10
innerSize := size - (margin * 2)
step := 15
surf := cairo.ImageSurfaceCreate(cairo.FormatARGB32, size, size)
cr := cairo.Create(surf.Surface)
cr.SetSourceRGB(1, 1, 1)
cr.Paint()
cr.SetAntialias(cairo.AntialiasBest)
// Offset by 0.5 to get pixel-aligned lines.
cr.Translate(float64(margin)+0.5, float64(margin)+0.5)
cr.SetSourceRGB(0, 0, 0)
cr.SetLineWidth(1)
for i := 0; i <= innerSize; i += step {
cr.MoveTo(0, float64(i))
cr.LineTo(float64(i), float64(innerSize))
cr.Stroke()
cr.MoveTo(float64(i), 0)
cr.LineTo(float64(innerSize), float64(i))
cr.Stroke()
}
surf.Flush()
f, err := os.Create("example.png")
if err != nil {
panic(err)
}
defer f.Close()
err = surf.WriteToPNG(f)
if err != nil {
panic(err)
}
}