From 2acdf8ef7f60a1e21a205db680b002a75a456ddf Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@gmail.com>
Date: Sat, 18 Jan 2020 12:40:16 +0000
Subject: [PATCH] Color dialog (windows).

---
 color_test.go    | 20 +++++++++++++
 color_windows.go | 76 ++++++++++++++++++++++++++++++++++++++++++++++++
 zenity.go        | 16 ++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 color_test.go
 create mode 100644 color_windows.go

diff --git a/color_test.go b/color_test.go
new file mode 100644
index 0000000..26baf03
--- /dev/null
+++ b/color_test.go
@@ -0,0 +1,20 @@
+package zenity_test
+
+import (
+	"image/color"
+
+	"github.com/ncruces/zenity"
+)
+
+func ExampleSelectColor() {
+	zenity.SelectColor(
+		zenity.Color(color.RGBA{R: 0x66, G: 0x33, B: 0x99, A: 0xff}))
+	// Output:
+}
+
+func ExampleSelectColor_palette() {
+	zenity.SelectColor(
+		zenity.ShowPalette(),
+		zenity.Color(color.RGBA{R: 0x66, G: 0x33, B: 0x99, A: 0xff}))
+	// Output:
+}
diff --git a/color_windows.go b/color_windows.go
new file mode 100644
index 0000000..cefeec5
--- /dev/null
+++ b/color_windows.go
@@ -0,0 +1,76 @@
+package zenity
+
+import (
+	"image/color"
+	"runtime"
+	"sync"
+	"unsafe"
+)
+
+var (
+	chooseColor = comdlg32.NewProc("ChooseColorW")
+
+	savedColors = [16]uint32{}
+	colorsMutex sync.Mutex
+)
+
+func init() {
+	for i := range savedColors {
+		savedColors[i] = 0xffffff
+	}
+}
+
+func SelectColor(options ...Option) (color.Color, error) {
+	opts := optsParse(options)
+
+	// load custom colors
+	colorsMutex.Lock()
+	customColors := savedColors
+	colorsMutex.Unlock()
+
+	var args _CHOOSECOLORW
+	args.StructSize = uint32(unsafe.Sizeof(args))
+	args.CustColors = &customColors
+
+	if opts.color != nil {
+		args.Flags |= 0x1 // CC_RGBINIT
+		r, g, b, _ := opts.color.RGBA()
+		args.RgbResult = (r >> 8 << 0) | (g >> 8 << 8) | (b >> 8 << 16)
+	}
+	if opts.palette {
+		args.Flags |= 4 // CC_PREVENTFULLOPEN
+	} else {
+		args.Flags |= 2 // CC_FULLOPEN
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	n, _, _ := chooseColor.Call(uintptr(unsafe.Pointer(&args)))
+
+	// save custom colors back
+	colorsMutex.Lock()
+	savedColors = customColors
+	colorsMutex.Unlock()
+
+	if n == 0 {
+		return nil, commDlgError()
+	}
+
+	r := uint8(args.RgbResult >> 0)
+	g := uint8(args.RgbResult >> 8)
+	b := uint8(args.RgbResult >> 16)
+	return color.RGBA{R: r, G: g, B: b, A: 255}, nil
+}
+
+type _CHOOSECOLORW struct {
+	StructSize   uint32
+	Owner        uintptr
+	Instance     uintptr
+	RgbResult    uint32
+	CustColors   *[16]uint32
+	Flags        uint32
+	CustData     uintptr
+	FnHook       uintptr
+	TemplateName *uint16
+}
diff --git a/zenity.go b/zenity.go
index f319cd9..8db4ec8 100644
--- a/zenity.go
+++ b/zenity.go
@@ -1,5 +1,7 @@
 package zenity
 
+import "image/color"
+
 // Errors
 
 type constError string
@@ -24,6 +26,10 @@ type options struct {
 	hidden    bool
 	filters   []FileFilter
 
+	// Color selection options
+	color   color.Color
+	palette bool
+
 	// Message options
 	icon      MessageIcon
 	ok        string
@@ -104,6 +110,16 @@ func (f FileFilters) Build() Option {
 	return func(o *options) { o.filters = append(o.filters, f...) }
 }
 
+// Color selection options
+
+func Color(c color.Color) Option {
+	return func(o *options) { o.color = c }
+}
+
+func ShowPalette() Option {
+	return func(o *options) { o.palette = true }
+}
+
 // Message options
 
 // MessageIcon is the enumeration for message dialog icons.