Get Image Type...
Posted: Sun Jun 10, 2007 3:03 am
If you like graphics, and like fooling around with images, you may have had a problem with an images extension not matching the real type of image format it is. Some real #$%$# can change the extension just to be funny guys.
Freeimage has "Freeimage_GetFormat", so in the spirit of the up and coming PB image library, here is my smaller, yet almost bulletproof version of that function.
The FINAL aim of this is to look at the extension of the file, and compare that to what format this function detects. If both correspond, then it will return a value of #totally_OK_to_Load. if the extension doesn't match the format, i know my detection methods are near bulletproof, so it will return #probably_ok_to_load. If NOTHING pans out, then I will give the user the option of #Load_at_all_costs_because_I_want_the_darn_image_NOW, and defer to heuristic image loading routines.
PLEASE, PLEASE, PLEASE, if you can add more detections to this, PLEASE DO!!!
Freeimage has "Freeimage_GetFormat", so in the spirit of the up and coming PB image library, here is my smaller, yet almost bulletproof version of that function.
The FINAL aim of this is to look at the extension of the file, and compare that to what format this function detects. If both correspond, then it will return a value of #totally_OK_to_Load. if the extension doesn't match the format, i know my detection methods are near bulletproof, so it will return #probably_ok_to_load. If NOTHING pans out, then I will give the user the option of #Load_at_all_costs_because_I_want_the_darn_image_NOW, and defer to heuristic image loading routines.
PLEASE, PLEASE, PLEASE, if you can add more detections to this, PLEASE DO!!!
Code: Select all
#Image_Unknown=0
#Image_DCX=1
#Image_GIF =2
#Image_PCX=3
#Image_JPEG=4
#Image_PNG=5
#Image_TGA=6
#Image_BMP_Win=7
#Image_BMP_OS2=8
#Image_Tiff=9
#Image_RAS=10
#Image_Pic=11
Macro SwapL(val)
(((val>>24) & $000000FF)|((val>>8) & $0000FF00)|((val<<8) & $00FF0000)|((val<<24) & $FF000000))
EndMacro
Procedure GetImageType(filename.s)
If FileSize(filename); make sure some idiot didnt send us a fake file
file=ReadFile(#PB_Any,filename)
If file ; OK, file is open
; let's try DCX, Magic # is FIRST long
Magic.l=ReadLong(file)
If Magic =987654321
CloseFile(file)
ProcedureReturn #Image_DCX
EndIf
; Let's try GIF next. fairly easy to spot
FileSeek(file,0)
gif=AllocateMemory(6)
ReadData(file,gif,6)
If PeekS(gif,6)= "GIF89a" Or PeekS(gif,6)= "GIF87a"
CloseFile(file)
FreeMemory(gif)
ProcedureReturn #Image_GIF
EndIf
FreeMemory(gif)
;Now JPEG
FileSeek(file,0)
byte.b=ReadByte(file)
byte1$=Right(Hex(byte),2)
byte.b=ReadByte(file)
byte1$+Right(Hex(byte),2)
FileSeek(file, Loc(file)+4)
jfif$=""
For a=0 To 3
jfif$=jfif$+Chr(ReadByte(file))
Next
If byte1$="FFD8" And jfif$="JFIF"
CloseFile(file)
ProcedureReturn #Image_JPEG
EndIf
;Now PNG
FileSeek(file,0)
For a=0 To 7
byte.b=ReadByte(file)
If a=0
rtn.s=Right(Hex(byte),2)
string$=string$+ rtn
Else
rtn.s=RSet(Hex(byte),2,"0")
string$=string$+ rtn
EndIf
Next
If string$="89504E470D0A1A0A"
CloseFile(file)
FreeMemory(st)
ProcedureReturn #Image_PNG
EndIf
;Now TGA
FileSeek(file,Lof(file)-18)
st=AllocateMemory(16)
ReadData(file,gif,16)
If PeekS(gif,16)= "TRUEVISION-XFILE"
CloseFile(file)
FreeMemory(st)
ProcedureReturn #Image_TGA
EndIf
FreeMemory(st)
;PCX
FileSeek(file,0)
st=AllocateMemory(4)
ReadData(file,st,4)
ident.b=PeekB(st)
Version.b=PeekB(st+1)
encoding=PeekB(st+2)
bitsPerPixel=PeekB(st+3)
If ident=10
If Version<=5 And encoding=1
ProcedureReturn #Image_PCX
EndIf
EndIf
FreeMemory(st)
;BMP (Windows)
FileSeek(file,0)
BM$=""
For a=0 To 1
BM$=BM$+Chr(ReadByte(file))
Next
FileSeek(file,14)
Size.b=ReadByte(file)
If BM$= "BM" And Size.b=40
ProcedureReturn #Image_BMP_Win
EndIf
;BMP (OS2)
FileSeek(file,0)
BM$=""
For a=0 To 1
BM$=BM$+Chr(ReadByte(file))
Next
FileSeek(file,14)
Size.b=ReadByte(file)
If BM$= "BM" And Size.b=12
ProcedureReturn #Image_BMP_OS2
EndIf
;TIFF
FileSeek(file,0)
MM$=""
For a=0 To 1
MM$=MM$+Chr(ReadByte(file))
Next
If MM$= "II" Or MM$="MM"
ProcedureReturn #Image_Tiff
EndIf
;RAS
FileSeek(file,0)
Magic.l=ReadLong(file)
Magic1.l= SwapL(Magic)
If Magic1 = 1504078485
ProcedureReturn #Image_RAS
EndIf
;uh, ok. Let's try .PIC/Pictor PC Paint
FileSeek(file,0)
id.w=ReadWord(file)
If id= $1234
ProcedureReturn #Image_Pic
EndIf
EndIf
Else
ProcedureReturn -1
EndIf
EndProcedure
If OpenWindow(0,0,0,470,420,"",#PB_Window_SystemMenu|#PB_Window_ScreenCentered) And CreateGadgetList(WindowID(0))
ButtonGadget(0, 10, 10,80,20,"OpenFile")
ImageGadget(1, 10, 50, 300,300,0,#PB_Image_Border)
EndIf
Repeat
Select WaitWindowEvent()
Case #PB_Event_Gadget
Select EventGadget()
Case 0
Pattern$ ="All Supported Formats|*.nif;*.BMP;*.gif;*.JPG;*.jpeg;*.tif;*.tiff;*.pcx;*.tga;*.png;*.iff;*.wbm;*.wbmp;*.dcx;*.ras;*.pic"
Pattern$ +"|New image Format (nif)|*.nif|BITMAP (bmp)|*.bmp|Graphics Interchange Format (gif)|*.gif|JPEG (jpg)|*.jpg;*.jpeg|TIFF (tif)|*.tif;*.tiff|Zsoft PainBrush (pcx)|*.pcx|Targa (tga)|*.tga|Portable Networks Graphic (png)|*.png|Amiga IFF (iff)|*.iff|Wireless Bitmap (wbm, wbmp)|*.wbm;*.wbmp|Pictor PC Paint (pic)|*.pic"
Pattern$+"|Windows Metafile (wmf, emf)|*.wmf;*.emf|Multipage PCX (dcx)|*.dcx"
filename.s = OpenFileRequester("Choose An Image File To Open","",Pattern$,0)
If filename
Debug GetImageType(filename)
EndIf
EndSelect
Case #PB_Event_CloseWindow
End
EndSelect
ForEver
