Merge pull request #5295 from andydotxyz/fix/1977

Fix/1977

internal/painter/gl/draw.go

@@ -264,10 +264,8 @@ func (p *painter) drawTextureWithDetails(o fyne.CanvasObject, creator func(canva
 	p.defineVertexArray(p.program, "vert", 3, 5, 0)
 	p.defineVertexArray(p.program, "vertTexCoord", 2, 5, 3)
 
-	// here we have to choose between blending the image alpha or fading it...
-	// TODO find a way to support both
 	if alpha != 1.0 {
-		p.ctx.BlendColor(0, 0, 0, alpha)
+		p.ctx.BlendColor(alpha, alpha, alpha, alpha)
 		p.ctx.BlendFunc(constantAlpha, oneMinusConstantAlpha)
 	} else {
 		p.ctx.BlendFunc(one, oneMinusSrcAlpha)

internal/painter/gl/shaders/simple.frag

@@ -5,5 +5,8 @@ uniform sampler2D tex;
 varying vec2 fragTexCoord;
 
 void main() {
-    gl_FragColor = texture2D(tex, fragTexCoord);
+    vec4 texColor = texture2D(tex, fragTexCoord);
+    if(texColor.a < 0.01)
+        discard;
+    gl_FragColor = texColor;
 }

internal/painter/software/draw.go

@@ -3,6 +3,7 @@ package software
 import (
 	"fmt"
 	"image"
+	"image/color"
 	"math"
 
 	"fyne.io/fyne/v2"
@@ -46,7 +47,7 @@ func drawGradient(c fyne.Canvas, g gradient, pos fyne.Position, base *image.NRGB
 	width := scale.ToScreenCoordinate(c, bounds.Width)
 	height := scale.ToScreenCoordinate(c, bounds.Height)
 	tex := g.Generate(width, height)
-	drawTex(scale.ToScreenCoordinate(c, pos.X), scale.ToScreenCoordinate(c, pos.Y), width, height, base, tex, clip)
+	drawTex(scale.ToScreenCoordinate(c, pos.X), scale.ToScreenCoordinate(c, pos.Y), width, height, base, tex, clip, 1.0)
 }
 
 func drawImage(c fyne.Canvas, img *canvas.Image, pos fyne.Position, base *image.NRGBA, clip image.Rectangle) {
@@ -75,13 +76,13 @@ func drawImage(c fyne.Canvas, img *canvas.Image, pos fyne.Position, base *image.
 		}
 	}
 
-	drawPixels(scaledX, scaledY, width, height, img.ScaleMode, base, origImg, clip)
+	drawPixels(scaledX, scaledY, width, height, img.ScaleMode, base, origImg, clip, img.Alpha())
 }
 
-func drawPixels(x, y, width, height int, mode canvas.ImageScale, base *image.NRGBA, origImg image.Image, clip image.Rectangle) {
+func drawPixels(x, y, width, height int, mode canvas.ImageScale, base *image.NRGBA, origImg image.Image, clip image.Rectangle, alpha float64) {
 	if origImg.Bounds().Dx() == width && origImg.Bounds().Dy() == height {
 		// do not scale or duplicate image since not needed, draw directly
-		drawTex(x, y, width, height, base, origImg, clip)
+		drawTex(x, y, width, height, base, origImg, clip, alpha)
 		return
 	}
 
@@ -99,7 +100,7 @@ func drawPixels(x, y, width, height int, mode canvas.ImageScale, base *image.NRG
 		draw.CatmullRom.Scale(scaledImg, scaledBounds, origImg, origImg.Bounds(), draw.Over, nil)
 	}
 
-	drawTex(x, y, width, height, base, scaledImg, clip)
+	drawTex(x, y, width, height, base, scaledImg, clip, alpha)
 }
 
 func drawLine(c fyne.Canvas, line *canvas.Line, pos fyne.Position, base *image.NRGBA, clip image.Rectangle) {
@@ -124,11 +125,16 @@ func drawLine(c fyne.Canvas, line *canvas.Line, pos fyne.Position, base *image.N
 	draw.Draw(base, bounds, raw, image.Point{offX, offY}, draw.Over)
 }
 
-func drawTex(x, y, width, height int, base *image.NRGBA, tex image.Image, clip image.Rectangle) {
+func drawTex(x, y, width, height int, base *image.NRGBA, tex image.Image, clip image.Rectangle, alpha float64) {
 	outBounds := image.Rect(x, y, x+width, y+height)
 	clippedBounds := clip.Intersect(outBounds)
 	srcPt := image.Point{X: clippedBounds.Min.X - outBounds.Min.X, Y: clippedBounds.Min.Y - outBounds.Min.Y}
-	draw.Draw(base, clippedBounds, tex, srcPt, draw.Over)
+	if alpha == 1.0 {
+		draw.Draw(base, clippedBounds, tex, srcPt, draw.Over)
+	} else {
+		mask := &image.Uniform{C: color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: uint8(float64(0xff) * alpha)}}
+		draw.DrawMask(base, clippedBounds, tex, srcPt, mask, srcPt, draw.Over)
+	}
 }
 
 func drawText(c fyne.Canvas, text *canvas.Text, pos fyne.Position, base *image.NRGBA, clip image.Rectangle) {
@@ -176,9 +182,9 @@ func drawRaster(c fyne.Canvas, rast *canvas.Raster, pos fyne.Position, base *ima
 
 	pix := rast.Generator(width, height)
 	if pix.Bounds().Bounds().Dx() != width || pix.Bounds().Dy() != height {
-		drawPixels(scaledX, scaledY, width, height, rast.ScaleMode, base, pix, clip)
+		drawPixels(scaledX, scaledY, width, height, rast.ScaleMode, base, pix, clip, 1.0)
 	} else {
-		drawTex(scaledX, scaledY, width, height, base, pix, clip)
+		drawTex(scaledX, scaledY, width, height, base, pix, clip, 1.0)
 	}
 }
 

internal/painter/software/painter_test.go

@@ -78,6 +78,20 @@ func TestPainter_paintImage(t *testing.T) {
 	test.AssertImageMatches(t, "draw_image_default.png", target)
 }
 
+func TestPainter_paintImageAlpha(t *testing.T) {
+	img := canvas.NewImageFromImage(makeTestImage(3, 3))
+	img.Translucency = 0.5
+
+	c := test.NewCanvas()
+	c.SetPadded(false)
+	c.SetContent(img)
+	c.Resize(fyne.NewSize(50, 50))
+	p := software.NewPainter()
+
+	target := p.Paint(c)
+	test.AssertImageMatches(t, "draw_image_alpha.png", target)
+}
+
 func TestPainter_paintImage_clipped(t *testing.T) {
 	test.ApplyTheme(t, test.Theme())
 	img := canvas.NewImageFromImage(makeTestImage(5, 5))

test/markup_renderer_test.go

@@ -140,12 +140,12 @@ func Test_snapshot(t *testing.T) {
 		"image with translucency": {
 			content: func() fyne.CanvasObject {
 				img := fynecanvas.NewImageFromResource(theme.ZoomOutIcon())
-				img.Translucency = 1.3
+				img.Translucency = 0.3
 				return img
 			}(),
 			want: "<canvas size=\"100x100\">\n" +
 				"\t<content>\n" +
-				"\t\t<image rsc=\"zoomOutIcon\" size=\"100x100\" themed=\"foreground\" translucency=\"1.3\"/>\n" +
+				"\t\t<image rsc=\"zoomOutIcon\" size=\"100x100\" themed=\"foreground\" translucency=\"0.3\"/>\n" +
 				"\t</content>\n" +
 				"</canvas>\n",
 		},