bitmap manipulation in PBWin?

[Frank Kestens]

I want to perform some transformations on bitmaps , especially the "world-maps" in which a globe is represented as a rectangle .
Is there some way to adress the individual pixels once the bitmap has been loaded in memory ? It would be usefull if I could get the bitmap in a nxm array .

[Bob Zale]

Sure. Just use GRAPHIC GET BITS to retrieve the data and GRAPHIC SET BITS to put it back.

Best regards,

Bob Zale

[Richard Angell]

some examples, albeit with different transformations, can be found in the forums as well as the DDT samples: {Drive}:\PBWin90\Samples\Ddt\Graphic\GraphicTransforms

[Frank Kestens]

Thanks Bob and Richard ! I can get along now .

[Frank Kestens]

Graphic Get Bits works fine , but I've a problem when I want to save a modified .bmp file . In fact the new mofified file saves , but it can't be read again , neither with normal viewers nor with the program itself .
The program hereunder reads a .bmp file , modifies some pixels and saves it .
Anybody has an idea what goes wrong ?

[Frank Kestens]

Same post as above but with the program listed :

#COMPILE EXE
#DIM NONE
FUNCTION PBMAIN () AS LONG
BmpName$ = INPUTBOX$(".... .bmp","Choose_Bmp.file")
OPEN BmpName$ FOR BINARY AS #1 ' Retrieving the width and the heifht of the bitmap '
GET #1, 19, nWidth&
GET #1, 23, nHeight&
CLOSE #1
GRAPHIC WINDOW "Converting pixels...", 1, 1, nWidth& , nHeight& TO hWin???
GRAPHIC ATTACH hWin???, 0
GRAPHIC RENDER BmpName$, (0, 0)-(nWidth&, nHeight&)
GRAPHIC SET POS(10,10): GRAPHIC PRINT nWidth&;nHeight&
LOCAL PixelPtr AS LONG PTR
GRAPHIC GET BITS TO bmpName1$
xsize& = CVL(bmpName1$,1)
ysize& = CVL(bmpName1$,5)
PixelPtr = STRPTR(bmpName1$) + 8
FOR i& = 1 TO xsize& * ysize&
a$=HEX$(@pixelptr)
REPLACE "F" WITH "B" IN a$ 'converting each " " with " "
@pixelptr=VAL("&H"+a$)
INCR PixelPtr
NEXT i&
GRAPHIC SET BITS bmpName1$
SLEEP 3000
' this doesn'r work when opening the file again
OPEN "result.bmp" FOR BINARY AS #1
SEEK # 1, 1
PUT$ #1 , bmpName1$
CLOSE #1
END FUNCTION

[Petr Schreiber jr]

Frank,

BMP files consist of header and RGB sequence, you example supplies just the ~RGB sequence.
While I could bother you with creating header, my answer will be short:

GRAPHIC SAVE "result.bmp"

The complete code then:

#COMPILE EXE
#DIM NONE

FUNCTION PBMAIN () AS LONG
    
    BmpName$ = INPUTBOX$(".... .bmp","Choose_Bmp.file")
    OPEN BmpName$ FOR BINARY AS #1 ' Retrieving the width and the heifht of the bitmap '
        GET #1, 19, nWidth&
        GET #1, 23, nHeight&
    CLOSE #1
    
    GRAPHIC WINDOW "Converting pixels...", 1, 1, nWidth& , nHeight& TO hWin???
    GRAPHIC ATTACH hWin???, 0
    
    GRAPHIC RENDER BmpName$, (0, 0)-(nWidth&, nHeight&)
    GRAPHIC SET POS(10,10): GRAPHIC PRINT nWidth&;nHeight&
    
    LOCAL PixelPtr AS LONG PTR
    GRAPHIC GET BITS TO bmpName1$
    xsize& = CVL(bmpName1$,1)
    ysize& = CVL(bmpName1$,5)
    PixelPtr = STRPTR(bmpName1$) + 8
    
    FOR i& = 1 TO xsize& * ysize&
        a$=HEX$(@pixelptr)
        REPLACE "F" WITH "B" IN a$ 'converting each " " with " "
        @pixelptr=VAL("&H"+a$)
        INCR PixelPtr
    NEXT i&
    
    GRAPHIC SET BITS bmpName1$
    
    SLEEP 3000
    
    GRAPHIC SAVE "result.bmp"
END FUNCTION

Petr

[Chris Holbrook]

Have you tried using GRAPHIC SAVE?

[Frank Kestens]

bitmaps save

Thanks Peter and Chris , this works !
The "easy" way with GRAPHIC SAVE works while I was trying to do this the hard way . I thought the instructions in my program would also transfer the headers , but obviously this isn't the case . I guess the instruction GRAPHIC GET BITS transforms some information from the original bitmap , which isn't set back when saving again , or ..?

[Frank Kestens]

bitmap manipulation

The code works wunderfull .
Here's some code to swap the red and blue tones in a bitmap .

LOCAL PixelPtr AS LONG PTR
GRAPHIC GET BITS TO bmpName1$
xsize& = CVL(bmpName1$,1)
ysize& = CVL(bmpName1$,5)
PixelPtr = STRPTR(bmpName1$) + 8
FOR i& = 1 TO xsize& * ysize&
a$=HEX$(@pixelptr)
r$=LEFT$(a$,2)
g$=MID$ (a$,3,2)
b$=RIGHT$(a$,2)
a$=b$+g$+r$
@pixelptr=VAL("&H"+a$)
INCR PixelPtr
NEXT i&
GRAPHIC SET BITS bmpName1$
SLEEP 3000
GRAPHIC SAVE "result.bmp"

[Edwin Knoppert]

I used it with msgbox statements and the modified image shows fine.
Sleep makes that it doesn't get updated.