I'm not quite ready but there should be gif support added to the axe modules shortly. Here is the reader in it's current state, use LoadImage(pixmap) with the pixmap result in my test code if you want to play with it:
' readgif.bmx
Strict
Global CODEMASK[]=[0,$0001,$0003,$0007,$000F,$001F,$003F,$007F,$00FF,$01FF,$03FF,$07FF,$0FFF]
Const MAXCODES=4096
Const HASALPHA=1
Global stack:Short[MAXCODES]
Global suffix:Short[MAXCODES]
Global prefix:Short[MAXCODES]
Global lzhbuffer:Byte[256]
Global bbptr,bits,bytes,bval
rem
'this is my testcode...
Local stream:TStream
Local pixmaps:TList
Local pix:TPixmap
stream=ReadFile("tweety.gif")
'stream=ReadFile("acidsoftware.gif")
'stream=ReadFile("grid.gif")
pixmaps=ReadGifPixmaps(stream)
pix=TPixmap(pixmaps.valueatindex(0))
SavePixmapPNG pix,"testpng.png"
endrem
Function ReadGifPixmaps:TList(stream:TStream)
Local pixmaps:TList=New TList
Local pix:TPixmap
Local pal:Int Ptr
Local bgcol
Local aspect
Local i,r,g,b,w,h,f,n,t
Local _delay,_start,_end,_loop,_flags
Local hdr:Byte[6]
If stream.Read(hdr,6)<>6 Return
If hdr[0]<>Asc("G") Or hdr[1]<>Asc("I") Or hdr[2]<>Asc("F") Return
' 89A
Print hdr[3]+Chr(hdr[3])
Print hdr[4]+Chr(hdr[4])
Print hdr[5]+Chr(hdr[5])
w=stream.ReadShort()
h=stream.ReadShort()
f=stream.ReadByte()
bgcol=stream.ReadByte()
aspect=stream.ReadByte()
If f&128
n=2Shl(f&7)
pal=New Int[n]
For i=0 Until n
r=stream.ReadByte()
g=stream.ReadByte()
b=stream.ReadByte()
pal[i]=$ff000000|(r Shl 16)|(g Shl 8)|(b)
Next
EndIf
_delay=-1
While True
n=stream.ReadByte()
Select n
Case -1
Return pixmaps
Case $2c
parsegif(pixmaps,stream,pal,0)
DebugLog "gif $2c complete pixmaps.count()="+pixmaps.count()
Return pixmaps
' DebugStop
Case $21
n=stream.ReadByte()
Select n
Case $f9'graphic control block
n=stream.ReadByte()
f=stream.ReadByte()
_delay=stream.ReadShort()
t=stream.ReadByte()
If f&1
pal[t]:&$ffffff
_flags=HASALPHA
EndIf
stream.seek(stream.pos()+n-4)
While True
n=stream.ReadByte()
If n=0 Exit
stream.seek(stream.pos()+n)
Wend
Default
n=stream.ReadByte()
stream.Seek stream.pos()+n
While True
n=stream.ReadByte()
If n=0 Exit
stream.seek(stream.pos()+n)
Wend
End Select
End Select
Wend
End Function
Function lzhread(stream:TStream,currsize)
Local i,r
If bits=0
If bytes<=0
bbptr=0
bytes=stream.readbyte()
For i=0 Until bytes
lzhbuffer[i]=stream.ReadByte()
Next
EndIf
bval=lzhbuffer[bbptr]
bbptr:+1
bits=8
bytes:-1
EndIf
r=bval Shr(8-bits)
While bits<currsize
If bytes<=0
bbptr=0
bytes=stream.ReadByte()
For i=0 Until bytes
lzhbuffer[i]=Stream.ReadByte()
Next
EndIf
bval=lzhbuffer[bbptr]
bbptr:+1
r:|(bval Shl bits)
bits:+8
bytes:-1
Wend
bits:-currsize
Return r&CODEMASK[currsize]
End Function
Function parsegif(pixmaps:TList,stream:TStream,pal:Int Ptr,flags,squash=False)
Local x,y,w,h,f 'i,r,g,b,n
Local size,csize,topslot,clear
Local ending,slot,newcodes,avail,bitsleft
Local c,code,oc,fc,sp,bptr
Local yinc,lpass
Local pix:TPixmap
x=stream.ReadShort()
y=stream.ReadShort()
w=stream.ReadShort()
h=stream.ReadShort()
f=stream.ReadByte()
yinc=1
If (f&64) yinc=8
DebugLog "createpixmap("+w+","+h+")"
If flags&HASALPHA
pix=CreatePixmap(w,h,PF_BGRA8888)
Else
pix=CreatePixmap(w,h,PF_BGR888)
EndIf
pixmaps.addlast pix
' can->SetHandle(-x,-y)
' If (squash)
' can->resize(w,(h+1)>>1,canflags,False)
' Else
' can->resize(w,h,canflags,False)
' image data
size=stream.readbyte()'system.debug("size="+size)
csize=size+1
topslot=1 Shl csize
clear=1 Shl size
ending=clear+1
slot=ending+1
newcodes=ending+1
bbptr=0
bits=0
bytes=0
bval=0
While True
c=lzhread(stream,csize)
If c=ending Exit
If c=clear
csize=size+1
slot=newcodes
topslot=1 Shl csize
While True
c=lzhread(stream,csize)
If c<>clear Exit
Wend
If c=ending Exit
If c>=slot c=0
oc=c
fc=c
' If (squash)
' If ((x&1)=(y&1)) WritePixel(x,y Shr 1,pal[c])
' Else
WritePixel(pix,x,y,pal[c])
' EndIf
x:+1
If x=w
x=0
y:+yinc
If y>=h
y=4 Shr lpass
yinc=y*2
lpass:+1
EndIf
EndIf
Else
code=c
If code>=slot
code=oc
stack[sp]=Short(fc) 'simon was here
sp:+1
EndIf
While code>=newcodes
stack[sp]=suffix[ code]
sp:+1
code=prefix[ code]
Wend
stack[sp]=Short(code) 'simon was here
sp:+1
If slot<topslot
fc=code
suffix[slot]=Short(fc)
prefix[slot]=Short(oc)
slot:+1
oc=c
EndIf
If slot>=topslot And csize<12
topslot=topslot Shl 1
csize:+1
EndIf
While sp>0
sp:-1
c=stack[sp]
If squash
If (y=h-1) Or (x&1)=(y&1)
WritePixel(pix,x,y Shr 1,pal[c])
EndIf
Else
WritePixel(pix,x,y,pal[c])
EndIf
x:+1
If x=w
x=0
y:+yinc
If y>=h
y=4 Shr lpass
yinc=y*2
lpass:+1
EndIf
EndIf
Wend
EndIf
Wend
End Function
or try the following untested wrapper:
Function LoadGif:TImage(url:Object)
Local stream:TStream
Local pixmaps:TList
Local pix:TPixmap
stream=ReadFile(url)
If stream
pixmaps=ReadGifPixmaps(stream)
CloseFile stream
If pixmaps
pix=TPixmap(pixmaps.valueatindex(0))
Return LoadImage(pix)
EndIf
EndIf
End Function
