IMAGECREATE() and GET problem

[Cpcdos]

Hello

i have a problem with IMAGECREATE() and GET commands

Code: Select all

BIT = 16
ScreenRes 1024, 768, BIT, 2

Dim As Any Ptr imageCur = ImageCreate(50, 50, 0, BIT)
Get (100, 100)-(200, 200), imageCur
Put (1, 1), ImageCur

When i put content of ImageCur, i have a 8bit image inftead 16Bit.. Why ?

Best Regards

[TJF]

How can you compile that code? BIT is a pre-defined macro!

When I rename BIT, it's working fine under Ubuntu / fbc-0.24. What output do you get by this code

Code: Select all

VAR BIT_ = 16
SCREENRES 1024, 768, BIT_, 2

VAR imageCur = IMAGECREATE(50, 50, 0, BIT_)
IF imageCur THEN
  GET (100, 100)-(200, 200), imageCur
  PUT (1, 1), ImageCur

  VAR w = 0, h = 0, bpp = 0, pitch = 0, pixdata = CAST(ANY PTR, 0), size = 0
  VAR i = IMAGEINFO(imagecur, w, h, bpp, pitch, pixdata, size)
  IMAGEDESTROY(imagecur)
  SCREEN 0
  ?"ImageInfo: "; i
  ?"    width: "; w
  ?"   heigth: "; h
  ?"      bpp: "; bpp
  ?"    pitch: "; pitch
  ?"  pixdata: "; pixdata
  ?"     size: "; size
  SLEEP
ELSE
  ?"ImageCreate failed"
END IF


bpp should be = 2 (bytes per pixel).

[Cpcdos]

With your code, i have this :

[fxm]

I don't understand the aim of this test.
My PC crashes because of image buffer overflow.

That works with a consistent GET compared to IMAGECREATE:

Code: Select all

VAR BIT_ = 16
SCREENRES 1024, 768, BIT_, 2
VAR imageCur = IMAGECREATE(50, 50, 0, BIT_)
IF imageCur THEN
  GET (100, 100)-(149, 149), imageCur
  PUT (1, 1), ImageCur

  VAR w = 0, h = 0, bpp = 0, pitch = 0, pixdata = CAST(ANY PTR, 0), size = 0
  VAR i = IMAGEINFO(imagecur, w, h, bpp, pitch, pixdata, size)
  IMAGEDESTROY(imagecur)
  SCREEN 0
  ?"ImageInfo: "; i
  ?"    width: "; w
  ?"   heigth: "; h
  ?"      bpp: "; bpp
  ?"    pitch: "; pitch
  ?"  pixdata: "; pixdata
  ?"     size: "; size
  SLEEP
ELSE
  ?"ImageCreate failed"
END IF


Code: Select all

ImageInfo:  0
    width:  50
   heigth:  50
      bpp:  2
    pitch:  112
  pixdata: 17072256
     size:  5632

[Cpcdos]

No solutions ?

[dkl]

The image is only 50x50 - that's too small to hold an area of 101x101 pixels. As a result there will be a buffer overflow during the GET statement.

I'm wondering though why FB doesn't do the bound check... maybe it's because it just writes into the given buffer, without caring what it is or contains. "Get" also supports writing into arrays and it does have a bounds check for that. So, I wonder whether it could be changed to assume being given a properly initialized fb.Image buffer if it's not an array. It should be ok, because ImageCreate() is the only sane way to create the buffer for Get to write into, but who knows - old code may still be passing manually allocated uninitialized buffers.

[Cpcdos]

Oups..

For be sure
i have dimensioned imagecur at 300x300 and captured 200x200 pixels.. i have the same problem :/
i have test this code

Code: Select all

imageCur = IMAGECREATE(300, 300, 0, 8)
Get (1, 1)-(200, 200), imageCur
PUT (500, 500), ImageCur

      w = 0 : h = 0 : bpp = 0 : pitch = 0 : pixdata = CAST(ANY PTR, 0) :  size = 0
      i = IMAGEINFO(imagecur, w, h, bpp, pitch, pixdata, size)
      IMAGEDESTROY(imagecur)
     locate 5,
      ?"ImageInfo: "; i
      ?"    width: "; w
      ?"   heigth: "; h
      ?"      bpp: "; bpp
      ?"    pitch: "; pitch
      ?"  pixdata: "; pixdata
      ?"     size: "; size

and i have this :

[dkl]

Perhaps it will work with Put's Pset mode, instead of the default Xor:

Code: Select all

PUT (500, 500), ImageCur, pset

[fxm]

How is defined your graphic screen?

[TJF]

This looks like different color bit settings between your dosbox frame buffer and the fbgfx. FB uses R:5-G:6-B:5 format. Try to adjust that in DosBox.

[Cpcdos]

Thank you dkl

this problem provient of PUT (500, 500), ImageCur, pset

my program work !

Thank's you all !

[fxm]

Inconsistency between:
IMAGECREATE(300, 300, 0, 8)
and
bpp : 2

=> risk of image buffer overflow?

[Cpcdos]

Ho yes !, i have replaced by 16 or 32
8 is ugly ;-)