_SCREENIMAGE Fuzzy [solved]

[TerryRitchie]

I found some funky behavior with _SCREENIMAGE. If the width of a screen shot exceeds 1024 (0 - 1023) the image always comes out fuzzy as though it is being resized.

Desktop& = _SCREENIMAGE(0, 0, 1023, 600) ' not fuzzy

Desktop& = _SCREENIMAGE(0, 0, 1024, 600) ' fuzzy (anything over 1023)

Desktop& = _SCREENIMAGE ' fuzzy if over 1024 wide

Bug perhaps?

[Pete]

Fuzzy? Trouble with tribbles, perhaps?

[bplus]

I found some funky behavior with _SCREENIMAGE. If the width of a screen shot exceeds 1024 (0 - 1023) the image always comes out fuzzy as though it is being resized.

Desktop& = _SCREENIMAGE(0, 0, 1023, 600) ' not fuzzy

Desktop& = _SCREENIMAGE(0, 0, 1024, 600) ' fuzzy (anything over 1023)

Desktop& = _SCREENIMAGE ' fuzzy if over 1024 wide

Bug perhaps?

Into what container are you viewing the image?

This demo from Wiki runs fine:

Code: QB64: [Select]

1. desktop& = _SCREENIMAGE
2. MaxScreenX& = _WIDTH(desktop&)
3. MaxScreenY& = _HEIGHT(desktop&)
4. '_FREEIMAGE desktop& 'free image after measuring screen(it is not displayed)
5. SCREEN _NEWIMAGE(MaxScreenX&, MaxScreenY&, 32) 'program window is sized to fit changed to 32 from 256
6. _SCREENMOVE _MIDDLE
7.  
8. _PUTIMAGE , desktop&, 0  '<<<  I added this
9.  
10.  

[bplus]

Here's another test (over 1024):

Code: QB64: [Select]

1. desktop& = _SCREENIMAGE
2. MaxScreenX& = _WIDTH(desktop&)
3. MaxScreenY& = _HEIGHT(desktop&)
4. _FREEIMAGE desktop& 'free image after measuring screen(it is not displayed)
5.  
6. partialDesk& = _SCREENIMAGE(200, 0, MaxScreenX&, MaxScreenY& - 30)
7. SCREEN _NEWIMAGE(MaxScreenX& - 200, MaxScreenY& - 30, 32) 'program window is sized to fit changed to 32 from 256
8. _DELAY .25
9. _SCREENMOVE 200, 40
10. FOR i = 1 TO 1000
11.     PRINT MaxScreenX& - 200; " X "; MaxScreenY& - 30,
12. NEXT
13. PRINT
14. _DELAY .25
15. partialDesk& = _SCREENIMAGE(200, 0, MaxScreenX&, MaxScreenY& - 30)
16. _DELAY .1
17. _PUTIMAGE , partialDesk&, 0 '<<<  I added this
18.  
19.  

[FellippeHeitor]

I get the same only when I run in a VM.

Even screen 0 goes blurry if wider than a certain number of columns, since it's an OpenGL graphical window in the end.

When I run on the Mac, any size goes well.

Likely boils down to a graphics card issue.

PS: I do most of my coding in said VM, which runs XP. I can never run a bplus demo without editing the source first, since all his demos go beyond my blur point.

PS2: reread the thread and noticed it's screenimage; mine gets blurry with newimage. Too late to post anything, to bed I go.

[TerryRitchie]

That was it Fell. I'm running everything in a Win10 VM so the tutorial has Win10 screen shots (I run Windows 7 on my computer).

I should have checked for that. It's strange behavior. From now on when I run across something "strange" I'll be sure to test it outside the VM first.

[bplus]

I can never run a bplus demo without editing the source first, since all his demos go beyond my blur point.

@FellippeHeitor,  Is this because image width is past 1024?

[FellippeHeitor]

Yeah :-)

[FellippeHeitor]

Actually, let me see what my blur point is; it might differ from Terry's.

I remember it had to do with powers of 2 indeed. Give me a minute.

[FellippeHeitor]

Mine goes without blur up until 1024. It's at 1025 that the blur begins.

Might be too subtle to notice. It's actually an extreme antialiasing that gets applied after that stretch point, which not only makes it look terrible but also slows down execution/framerate greatly.

Again, only on the Windows VM. The Linux VM, same VirtualBox installation, renders large windows fine. It's Windows that doesn't play well with the graphics card virtualization here.

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[bplus]

Hi @FellippeHeitor

OK so now I am wondering about screen height, also a 2^n, maybe 512?

But that would mean 800 x 600 is no good either.

[FellippeHeitor]

No issues with screen height.

[TerryRitchie]

No issues with screen height.

Same here, never had a problem with height, only width.