Added ColorButton. Will fill in the rest of the histogram example later.

colorbutton.go

@@ -0,0 +1,83 @@
+// 12 december 2015
+
+package ui
+
+import (
+	"unsafe"
+)
+
+// #include <stdlib.h>
+// #include "ui.h"
+// #include "util.h"
+// extern void doColorButtonOnChanged(uiColorButton *, void *);
+// // see golang/go#19835
+// typedef void (*colorButtonCallback)(uiColorButton *, void *);
+// typedef struct pkguiCColor pkguiCColor;
+// struct pkguiCColor { double *r; double *g; double *b; double *a; };
+// static inline pkguiCColor pkguiNewCColor(void)
+// {
+// 	pkguiCColor c;
+// 
+// 	c.r = (double *) pkguiAlloc(4 * sizeof (double));
+// 	c.g = c.r + 1;
+// 	c.b = c.g + 1;
+// 	c.a = c.b + 1;
+// 	return c;
+// }
+// static inline void pkguiFreeCColor(pkguiCColor c)
+// {
+// 	free(c.r);
+// }
+import "C"
+
+// ColorButton is a Control that represents a button that the user can
+// click to select a color.
+type ColorButton struct {
+	ControlBase
+	b	*C.uiColorButton
+	onChanged		func(*ColorButton)
+}
+
+// NewColorButton creates a new ColorButton.
+func NewColorButton() *ColorButton {
+	b := new(ColorButton)
+
+	b.b = C.uiNewColorButton()
+
+	C.uiColorButtonOnChanged(b.b, C.colorButtonCallback(C.doColorButtonOnChanged), nil)
+
+	b.ControlBase = NewControlBase(b, uintptr(unsafe.Pointer(b.b)))
+	return b
+}
+
+// Color returns the color currently selected in the ColorButton.
+// Colors are not alpha-premultiplied.
+// TODO rename b or bl
+func (b *ColorButton) Color() (r, g, bl, a float64) {
+	c := C.pkguiNewCColor()
+	defer C.pkguiFreeCColor(c)
+	C.uiColorButtonColor(b.b, c.r, c.g, c.b, c.a)
+	return float64(*(c.r)), float64(*(c.g)), float64(*(c.b)), float64(*(c.a))
+}
+
+// SetColor sets the currently selected color in the ColorButton.
+// Colors are not alpha-premultiplied.
+// TODO rename b or bl
+func (b *ColorButton) SetColor(r, g, bl, a float64) {
+	C.uiColorButtonSetColor(b.b, C.double(r), C.double(g), C.double(bl), C.double(a))
+}
+
+// OnChanged registers f to be run when the user changes the
+// currently selected color in the ColorButton. Only one function
+// can be registered at a time.
+func (b *ColorButton) OnChanged(f func(*ColorButton)) {
+	b.onChanged = f
+}
+
+//export doColorButtonOnChanged
+func doColorButtonOnChanged(bb *C.uiColorButton, data unsafe.Pointer) {
+	b := ControlFromLibui(uintptr(unsafe.Pointer(bb))).(*ColorButton)
+	if b.onChanged != nil {
+		b.onChanged(b)
+	}
+}

zz_histogram.go

@@ -11,6 +11,8 @@ import (
 	"github.com/andlabs/ui"
 )
 
+var colorButton *ui.ColorButton
+
 var datapoints [10]*ui.Spinbox
 
 // some metrics
@@ -234,18 +236,17 @@ func setupUI() {
 		vbox.Append(datapoints[i], false)
 	}
 
-/*
-	colorButton = uiNewColorButton();
+	colorButton = ui.NewColorButton()
 	// TODO inline these
-	setSolidBrush(&brush, colorDodgerBlue, 1.0);
-	uiColorButtonSetColor(colorButton,
-		brush.R,
+	brush := mkSolidBrush(colorDodgerBlue, 1.0);
+	colorButton.SetColor(brush.R,
 		brush.G,
 		brush.B,
-		brush.A);
-	uiColorButtonOnChanged(colorButton, onColorChanged, NULL);
-	uiBoxAppend(vbox, uiControl(colorButton), 0);
-*/
+		brush.A)
+	colorButton.OnChanged(func(*ui.ColorButton) {
+		histogram.QueueRedrawAll()
+	})
+	vbox.Append(colorButton, false)
 
 	hbox.Append(histogram, true)