Merge pull request #935 from cjbrigato/frameless_movable_example

Transparent example: makes frameless windows movable

examples/transparent/transparent.go

@@ -10,11 +10,47 @@ import (
 	g "github.com/AllenDang/giu"
 )
 
+var (
+	wnd           *g.MasterWindow
+	isMovingFrame = false
+)
+
+func framelessMovableWidget(widget g.Widget) *g.CustomWidget {
+	return g.Custom(func() {
+		if isMovingFrame && !g.IsMouseDown(g.MouseButtonLeft) {
+			isMovingFrame = false
+			return
+		}
+
+		widget.Build()
+
+		if g.IsItemHovered() {
+			if g.IsMouseDown(g.MouseButtonLeft) {
+				isMovingFrame = true
+			}
+		}
+
+		if isMovingFrame {
+			delta := imgui.CurrentIO().MouseDelta()
+			dx := int(delta.X)
+			dy := int(delta.Y)
+
+			if dx != 0 || dy != 0 {
+				ox, oy := wnd.GetPos()
+				wnd.SetPos(ox+dx, oy+dy)
+			}
+		}
+	})
+}
+
 func loop() {
 	imgui.PushStyleVarFloat(imgui.StyleVarWindowBorderSize, 0)
-	g.PushColorWindowBg(color.RGBA{50, 50, 50, 0})
-	g.PushColorFrameBg(color.RGBA{10, 10, 10, 0})
+	g.PushColorWindowBg(color.RGBA{50, 50, 70, 130})
+	g.PushColorFrameBg(color.RGBA{30, 30, 60, 110})
 	g.SingleWindow().Layout(
+		framelessMovableWidget(
+			g.Label("Maintain Left-click on me to move the frameless window !"),
+		),
 		g.Custom(func() {
 			canvas := g.GetCanvas()
 			pos := g.GetCursorScreenPos()
@@ -48,7 +84,8 @@ func loop() {
 }
 
 func main() {
-	wnd := g.NewMasterWindow("transparent", 300, 200, g.MasterWindowFlagsNotResizable|g.MasterWindowFlagsFloating|g.MasterWindowFlagsFrameless|g.MasterWindowFlagsTransparent)
+	wnd = g.NewMasterWindow("transparent", 300, 200, g.MasterWindowFlagsNotResizable|g.MasterWindowFlagsFloating|g.MasterWindowFlagsFrameless|g.MasterWindowFlagsTransparent)
 	wnd.SetBgColor(color.RGBA{0, 0, 0, 0})
+	wnd.SetPos(50, 50)
 	wnd.Run(loop)
 }