Pic.Draw Transparency Pixel Glitch

[AlexH]

What is it you are trying to achieve?
Create a sniper reticule that works on Mouse.Where


What is the problem you are having?
Transparency is glitching, certain pixels remain white.



Describe what you have tried to solve this problem
colourback (), bmp, 32bit, 24bit, 8bit, jpg, resolution settings, picMerge, picUnderMerge


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)
<Answer Here>

Turing:

View.Set ("Graphics,offscreenonly,position:center;center,nobuttonbar") var x, y : int var click : int := 0 var scope : int := Pic.FileNew ("Scope2.jpg") scope := Pic.Scale (scope, 1500, 900) loop     Mouse.Where (x, y, click)     delay (3)     cls     Draw.FillBox (0, 0, 100, 100, black)     Draw.FillBox (100, 100, 200, 200, black)     Draw.FillBox (200, 200, 300, 300, black)     colourback (0)     Pic.Draw (scope, x - 750, y - 450, picMerge)     View.Update end loop

Please specify what version of Turing you are using
4.1.1

[AlexH]

Heres the image

[Tony]

my guess is that Pic.Scale might be getting certain pixels to slightly change their colour; or you have colour distortion in the source image itself.

[AlexH]

I tried removing pic.Scale and it just made the whole thing smaller (including the pixels).
And I have redone the reticule multiple times, I am positive it is solid white.
Using photoshop I have tried saving it while the white circle part is transparent or solid white. Neither worked.


Could you try it. To see if it is just my computer?
I am running Turing on Crossover on a mac.

[Tony]

AlexH @ Thu Dec 10, 2009 10:49 pm wrote:

it just made the whole thing smaller (including the pixels).

Sounds like the problem is with the source image. JPEG is a compressed format and it has artifacts.

[Euphoracle]

Try this image and see if you have better luck. I roughly recreated it in photoshop but did some tricky jpg compression so hopefully it doesn't distort the transparency part. If it works, if you want, I can do it to match the same position/size/colour as the one you posted (after my calc exam).

[AlexH]

I just jacked up the resolution to 3000 and the image size to 2000x1200.
And it made it slightly better. It will work for now.

[DtY]

Euphoracle @ Fri Dec 11, 2009 7:01 am wrote:

I roughly recreated it in photoshop but did some tricky jpg compression

Jpeg doesn't support an alpha channel, it's for photographs.

[Tony]

Turing's Transparency is based on a solid "transparent" colour, not alpha channel anyway.

But JPEG's lossy compression creates artifacts, see

http://en.wikipedia.org/wiki/Jpeg#Compression_ratio_and_artifacts

If you were to sample the "white pixels", you will see that they are not actually "white"

Large areas that become transparent are [254, 254, 254]. Most of the pixel artefacts are [253, 253, 253]

Some are [255, 253, 254].

[Euphoracle]

DtY @ Fri Dec 11, 2009 4:51 pm wrote:

Euphoracle @ Fri Dec 11, 2009 7:01 am wrote:

I roughly recreated it in photoshop but did some tricky jpg compression

Jpeg doesn't support an alpha channel, it's for photographs.

Who said anything about an alpha channel?