A better way to set image pixels (With Example)

[coconParticipant]

I have a case where I want to modify the pixels of an image. So based on trying a few stuff I result to this example.

Monkey

#Import "<std>" #Import "<mojo>" Using std.. Using mojo.. Class MyWindow Extends Window Field canvasDraw:Canvas Field canvasImage:Image Field imageWidth:Int, imageHeight:Int Method New() Super.New("", 800, 600) Local loadedImage := Image.Load("C:/___.jpg") imageWidth= loadedImage.Width imageHeight= loadedImage.Height canvasImage = New Image(imageHeight, imageHeight, PixelFormat.RGBA8, TextureFlags.Dynamic) canvasDraw = New Canvas(canvasImage) canvasDraw.DrawImage(loadedImage, 0, 0) canvasDraw.Flush() End Method OnRender(canvas:Canvas) Override App.RequestRender() If (Mouse.ButtonDown(MouseButton.Left)) For Local i := 0 To 100 Local pix := canvasDraw.CopyPixmap(canvasDraw.Viewport) Local color := pix.GetPixel(imgRndX, imgRndY) pix.SetPixel(imgRndX, imgRndY, color) canvasImage.Texture.PastePixmap(pix, 0, 0) canvasDraw.Flush() Next End canvas.DrawImage(canvasImage, 0, 0) End Property imgRndX:Int() Return Rnd(0, imageWidth) End Property imgRndY:Int() Return Rnd(0, imageHeight) End End Function Main() New AppInstance New MyWindow App.Run() End

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#Import "<std>" #Import "<mojo>" Using std.. Using mojo..     Class MyWindow Extends Window Field canvasDraw:Canvas Field canvasImage:Image Field imageWidth:Int, imageHeight:Int Method New() Super.New("", 800, 600) Local loadedImage := Image.Load("C:/___.jpg") imageWidth= loadedImage.Width imageHeight= loadedImage.Height canvasImage = New Image(imageHeight, imageHeight, PixelFormat.RGBA8, TextureFlags.Dynamic) canvasDraw = New Canvas(canvasImage) canvasDraw.DrawImage(loadedImage, 0, 0) canvasDraw.Flush() End Method OnRender(canvas:Canvas) Override App.RequestRender() If (Mouse.ButtonDown(MouseButton.Left)) For Local i := 0 To 100 Local pix := canvasDraw.CopyPixmap(canvasDraw.Viewport) Local color := pix.GetPixel(imgRndX, imgRndY) pix.SetPixel(imgRndX, imgRndY, color) canvasImage.Texture.PastePixmap(pix, 0, 0) canvasDraw.Flush() Next End canvas.DrawImage(canvasImage, 0, 0) End Property imgRndX:Int() Return Rnd(0, imageWidth) End Property imgRndY:Int() Return Rnd(0, imageHeight) End End   Function Main() New AppInstance New MyWindow App.Run() End

This example works fine, but if in the future are better ways that allow moving pixels directly (without allocating new Pixmaps) it wll be much preferred.

Monkey

canvasImage.Texture.SetPixel(p, imgRndX, imgRndY)

1	canvasImage.Texture.SetPixel(p, imgRndX, imgRndY)

[PhatPeterParticipant]

That is a slow way to access pixel, what stops you from just using texture via canvas and draw it permanently onto that like this?

Monkey

#Import "<std>" #Import "<mojo>" #Import "assets/" Using std.. Using mojo.. Class MyWindow Extends Window Field canvasDraw:Canvas Field canvasImage:Image Field x:Int Field xd:Int = 10 Method New() Super.New("", 800, 600) canvasImage = New Image(512, 512, PixelFormat.RGBA8, TextureFlags.Dynamic) canvasDraw = New Canvas(canvasImage) Local loadedImage := Image.Load("asset::picture.jpg") canvasDraw.DrawImage(loadedImage, 0, 0) canvasDraw.Flush() End Method OnRender(canvas:Canvas) Override App.RequestRender() If (Mouse.ButtonDown(MouseButton.Left)) For Local i := 0 To 10000 canvasDraw.DrawRect(Int(Rnd(0,511)),Int(Rnd(0,511)),1,1) ' Plot a single pixel ' pix := canvasDraw.CopyPixmap(canvasDraw.Viewport) ' pix.GetPixel(imgRndX, imgRndY) ' pix.SetPixel(imgRndX, imgRndY, color) ' canvasImage.Texture.SetPixel(p, imgRndX, imgRndY) ' canvasImage.Texture.PastePixmap(pix, 0, 0) Next canvasDraw.Flush() End canvas.DrawImage(canvasImage, x, 0) x=x+xd If xd > 0 And x >= (800-512) Then xd = -xd If xd < 0 And x <= (0) Then xd = -xd End End Function Main() New AppInstance New MyWindow App.Run() End

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#Import "<std>" #Import "<mojo>" #Import "assets/" Using std.. Using mojo..   Class MyWindow Extends Window Field canvasDraw:Canvas Field canvasImage:Image Field x:Int Field xd:Int = 10 Method New() Super.New("", 800, 600) canvasImage = New Image(512, 512, PixelFormat.RGBA8, TextureFlags.Dynamic) canvasDraw = New Canvas(canvasImage) Local loadedImage := Image.Load("asset::picture.jpg") canvasDraw.DrawImage(loadedImage, 0, 0) canvasDraw.Flush() End Method OnRender(canvas:Canvas) Override App.RequestRender()   If (Mouse.ButtonDown(MouseButton.Left)) For Local i := 0 To 10000 canvasDraw.DrawRect(Int(Rnd(0,511)),Int(Rnd(0,511)),1,1) ' Plot a single pixel ' pix := canvasDraw.CopyPixmap(canvasDraw.Viewport) ' pix.GetPixel(imgRndX, imgRndY) ' pix.SetPixel(imgRndX, imgRndY, color) ' canvasImage.Texture.SetPixel(p, imgRndX, imgRndY) ' canvasImage.Texture.PastePixmap(pix, 0, 0) Next canvasDraw.Flush() End   canvas.DrawImage(canvasImage, x, 0)   x=x+xd If xd > 0 And x >= (800-512) Then xd = -xd If xd < 0 And x <= (0) Then xd = -xd End   End Function Main() New AppInstance New MyWindow App.Run() End

[coconParticipant]

So using the canvas is faster right? OK I will result to it then. But still I would try a few other things if I can get it done.

[abakoboParticipant]

read this post for pixel by pixel read/write optimisation:

Faster way to read in pixels?

[coconParticipant]

Good one!

[Author]

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