0.0.14 Added drawing area. /JL

canvas.go

@@ -0,0 +1,13 @@
+package main
+
+import "github.com/lxn/walk"
+
+type (
+	Canvas struct {
+		*walk.Canvas
+	}
+)
+
+func NewCanvas() *Canvas {
+	return new(Canvas)
+}

images/README

@@ -0,0 +1,4 @@
+Most image files in this directory are from the base icon theme of the
+Tango Desktop Project at http://tango.freedesktop.org.
+
+Thanks for releasing those to the Public Domain.

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"log"
+	"math"
 
 	"github.com/lxn/walk"
 	. "github.com/lxn/walk/declarative"
@@ -10,7 +11,8 @@ import (
 type MyMainWindow struct {
 	*walk.MainWindow
 	colors         *walk.ScrollView
-	canvas         *walk.ScrollView
+	canvasscroll   *walk.ScrollView
+	drawWidget     *walk.CustomWidget
 	properties     *walk.ScrollView
 	pallette       Pallette
 	beads          []*BeadColor
@@ -24,7 +26,7 @@ type MyMainWindow struct {
 
 const (
 	AppName   string = "BeadImager"
-	Version   string = "0.0.13"
+	Version   string = "0.0.14"
 	CopyRight string = "©2022 Jan Lerking"
 	STD_MESS  string = "Ready"
 	UserPath  string = "C:\\Users\\janle\\BeadImager"
@@ -163,8 +165,16 @@ func main() {
 						Layout: VBox{},
 						Children: []Widget{
 							ScrollView{
-								AssignTo: &mw.canvas,
+								AssignTo: &mw.canvasscroll,
 								Layout:   VBox{MarginsZero: true},
+								Children: []Widget{
+									CustomWidget{
+										AssignTo:            &mw.drawWidget,
+										ClearsBackground:    true,
+										InvalidatesOnResize: true,
+										Paint:               mw.drawStuff,
+									},
+								},
 							},
 						},
 					},
@@ -186,3 +196,121 @@ func main() {
 		log.Fatal(err)
 	}
 }
+
+func (mw *MyMainWindow) drawStuff(canvas *walk.Canvas, updateBounds walk.Rectangle) error {
+	bmp, err := createBitmap()
+	if err != nil {
+		return err
+	}
+	defer bmp.Dispose()
+
+	bounds := mw.drawWidget.ClientBounds()
+
+	rectPen, err := walk.NewCosmeticPen(walk.PenSolid, walk.RGB(255, 0, 0))
+	if err != nil {
+		return err
+	}
+	defer rectPen.Dispose()
+
+	if err := canvas.DrawRectangle(rectPen, bounds); err != nil {
+		return err
+	}
+
+	ellipseBrush, err := walk.NewHatchBrush(walk.RGB(0, 255, 0), walk.HatchCross)
+	if err != nil {
+		return err
+	}
+	defer ellipseBrush.Dispose()
+
+	if err := canvas.FillEllipse(ellipseBrush, bounds); err != nil {
+		return err
+	}
+
+	linesBrush, err := walk.NewSolidColorBrush(walk.RGB(0, 0, 255))
+	if err != nil {
+		return err
+	}
+	defer linesBrush.Dispose()
+
+	linesPen, err := walk.NewGeometricPen(walk.PenDash, 8, linesBrush)
+	if err != nil {
+		return err
+	}
+	defer linesPen.Dispose()
+
+	if err := canvas.DrawLine(linesPen, walk.Point{bounds.X, bounds.Y}, walk.Point{bounds.Width, bounds.Height}); err != nil {
+		return err
+	}
+	if err := canvas.DrawLine(linesPen, walk.Point{bounds.X, bounds.Height}, walk.Point{bounds.Width, bounds.Y}); err != nil {
+		return err
+	}
+
+	points := make([]walk.Point, 10)
+	dx := bounds.Width / (len(points) - 1)
+	for i := range points {
+		points[i].X = i * dx
+		points[i].Y = int(float64(bounds.Height) / math.Pow(float64(bounds.Width/2), 2) * math.Pow(float64(i*dx-bounds.Width/2), 2))
+	}
+	if err := canvas.DrawPolyline(linesPen, points); err != nil {
+		return err
+	}
+
+	bmpSize := bmp.Size()
+	if err := canvas.DrawImage(bmp, walk.Point{(bounds.Width - bmpSize.Width) / 2, (bounds.Height - bmpSize.Height) / 2}); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func createBitmap() (*walk.Bitmap, error) {
+	bounds := walk.Rectangle{Width: 200, Height: 200}
+
+	bmp, err := walk.NewBitmap(bounds.Size())
+	if err != nil {
+		return nil, err
+	}
+
+	succeeded := false
+	defer func() {
+		if !succeeded {
+			bmp.Dispose()
+		}
+	}()
+
+	canvas, err := walk.NewCanvasFromImage(bmp)
+	if err != nil {
+		return nil, err
+	}
+	defer canvas.Dispose()
+
+	brushBmp, err := walk.NewBitmapFromFile("images/plus.png")
+	if err != nil {
+		return nil, err
+	}
+	defer brushBmp.Dispose()
+
+	brush, err := walk.NewBitmapBrush(brushBmp)
+	if err != nil {
+		return nil, err
+	}
+	defer brush.Dispose()
+
+	if err := canvas.FillRectangle(brush, bounds); err != nil {
+		return nil, err
+	}
+
+	font, err := walk.NewFont("Times New Roman", 40, walk.FontBold|walk.FontItalic)
+	if err != nil {
+		return nil, err
+	}
+	defer font.Dispose()
+
+	if err := canvas.DrawText("Walk Drawing Example", font, walk.RGB(0, 0, 0), bounds, walk.TextWordbreak); err != nil {
+		return nil, err
+	}
+
+	succeeded = true
+
+	return bmp, nil
+}