The GetImagePitch function returns the Pitch of a selected image. The pitch is the number of bytes that a single row of pixels uses. This information is used to calculate the Y coordinate when manually rendering pixels to a surface.
FACTS:
* The GetImagePtr(), () & GetImageDepth() functions are used to manually read/write pixels to/from PlayBASIC images.
* The image must be locked before you manually access it ! See (LockBuffer)
Mini Tutorial:
This example creates four images then manually Pokes pixels to each of them.
Cls RGB(0,0,255)
; create four images in each in a different video format
w=128
h=256
CreateFXImageEx 1,w,h,15 ; 15bit version
CreateFXImageEx 2,w,h,16 ; 16bit version
CreateFXImageEx 3,w,h,24 ; 24bit version
CreateFXImageEx 4,w,h,32 ; 32bit version
; Draw them to the screen
Xpos=60
Ypos=50
For i=1 To 4
FillImage(i)
Text Xpos,Ypos, "Address:"+Str$(GetImagePtr(i))
Text Xpos,Ypos+20," Pitch:"+Str$(GetImagePitch(i))
Text Xpos,Ypos+40," Depth:"+Str$(GetImageDepth(i))
DrawImage i,Xpos,Ypos+60,false
Xpos=Xpos+w+40
Next
; show the screen and wait for user to press a key
Sync
WaitKey
Function FillImage(ThisImage)
RenderToImage ThisImage
LockBuffer
Address =GetImagePtr(ThisImage)
Pitch =GetImagePitch(ThisIMage)
Depth =GetImageDepth(ThisImage)
Colour=0
For ylp=0 To GetImageHeight(ThisImage)-1
Colour2=colour
For xlp=0 To GetImageWidth(ThisImage)-1
PokePixel(Address,Pitch,Depth,Xlp,Ylp,Colour2)
Colour2=Colour2+1
Next
Colour=RgbAlphaAdd(Colour,$020101)
Next
UnLockBuffer
RenderToScreen
EndFunction
;*=------------------------------------------------------=*
; >> Generic Poke Pixel Routine <<
;*=-----------------------------------------------------=*
Psub PokePixel(Address,Pitch,Depth,Xpos,Ypos,Colour)
If Address<>0
Select Depth
Case 15 ; 16bit RGB 555 format
R=LSL16((RgbR(colour) & $f8),7)
G=LSL16((RgbG(colour) & $f8),2)
B=LSR16((RgbB(colour) & $f8),3)
PokeWord Address+(ypos*pitch)+(xpos*2), R | G | B
Case 16
R=LSL16((RgbR(colour) & $f8),8)
G=LSL16((RgbG(colour) & $fc),3)
B=LSR16((RgbB(colour) & $f8),3)
PokeWord Address+(ypos*pitch)+(xpos*2), R | G | B
Case 24 ; 24bit RGB's
R=RgbR(colour)
G=RgbG(colour)
B=RgbB(colour)
Address=Address+(Ypos*pitch)+(xpos*3)
PokeByte Address,R
PokeByte Address+1,G
PokeByte Address+2,B
Case 32 ; 32bit RGB either XRGB (-888) format or (ARGB 8888) format
PokeInt Address+(Ypos*Pitch)+(Xpos*4),COlour
EndSelect
EndIf
EndPsub
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