SaveImage() and depths < 24 bits

[Rings]

his error is still not solved.
PB4 can now create images in 8 bit,
the images is correctly converted,
but PB4 cannot save them in the format
given in CreateImage.

see this example code and the size of the saved' bitmap

Code: Select all

Procedure MakeDesktopScreenshot(ImageNr,x,y,Width,Height,depth) 
   hImage = CreateImage(ImageNr,Width,Height,depth) 
   hDC    = StartDrawing(ImageOutput(ImageNr)) 
   DeskDC = GetDC_(GetDesktopWindow_()) 
      BitBlt_(hDC,0,0,Width,Height,DeskDC,x,y,#SRCCOPY) 
   StopDrawing() 
   ReleaseDC_(GetDesktopWindow_(),DeskDC) 
   ProcedureReturn hImage 
EndProcedure

ScreenWidth = GetSystemMetrics_(#SM_CXSCREEN)
ScreenHeight = GetSystemMetrics_(#SM_CYSCREEN)
ColorDepth = GetDeviceCaps_(GetDC_(0),#BITSPIXEL)
Debug ColorDepth
;t1=GetTickCount_()
MakeDesktopScreenshot(0, 0, 0, ScreenWidth, ScreenHeight,8) 
;t2=GetTickCount_()
SaveImage(0, "C:\DesktopScreenshot.bmp");save always as screendepth
;t3=GetTickCount_()
;MessageRequester("Info",Str(t2-t1)+":"+Str(t3-t2),0)

and btw, try with 4 or 2 as depth

[Fred]

Yes, it's more an issue than a bug, the format differents than 24 bits are not support for SaveSprite/SaveImage().

[Joakim Christiansen]

Would be very handy to support that. Is there any other methods we can use? I really need to be able to save jpegs as 8-16 bit pictures.

[PB]

> I really need to be able to save jpegs as 8-16 bit pictures

Is that even possible? I thought JPEGs were only 24bit for color, and 8bit for grey?

[Kaeru Gaman]

the format differents than 24 bits are not support for SaveSprite/SaveImage().

I think it's time to add this.
there are functions that need 8bit images, like AlphaSprite or Terrain.
at the moment it is not possible to create ressources for them with a PB-code.

[Joakim Christiansen]

Is that even possible? I thought JPEGs were only 24bit for color, and 8bit for grey?

Not sure really, but 16bit would be handy. So I hope it does support at least that.
All I want is just less colors so my picture can take less space, and it would be handy for both jpg and png's.

[PB]

> 16bit would be handy. So I hope it does support at least that.

I was right, it's only 24bits:

"The second fundamental advantage of JPEG is that it stores full color
information: 24 bits/pixel (16 million colors)."

Source: http://www.faqs.org/faqs/jpeg-faq/part1/

[Kaeru Gaman]

ok, but I don't really care about JPG.

PNG is incredibly flexible, able to serve a lot of formats,
even 16bit grayscale or 64bit RGBA is a legal PNG-format.

it would really be nice and handy to properly solve all advantages of PNG,
including the compression-rate.

[PB]

> I don't really care about JPG

I wasn't talking to you.

[Kaeru Gaman]

hummm.. ok

he was talking about "jpegs as 8-16 bit" literally..

anyhow, BMP and PNG serve other bitdepths and thus should be supported.

[Kaeru Gaman]

Yes, it's more an issue than a bug, the format differents than 24 bits are not support for SaveSprite/SaveImage().

I know I'm repeating myself, but I want to make it clear:

if you want to create HeightFields on your own, it is absolutely necessary
to be able to save 8bit resp. 16bit grayscale PNGs.

without this feature, you cannot use PB to wright your own Terrain-Creator-Tool.

I strongly recommend to add this feature latest along with newest OGRE in PB 4.30