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Large PICTs
Large 'PICT's How to display large 'PICT's
Early versions of the Macintosh ROMs don't let you use 'PICT' resources over
32K. There are two ways you can work around this:
• Instead of storing a 'PICT' in a resource, you can store it in a PICT file, a
file with a 'PICT' stored in its data fork. The example below shows you how
to read in a 'PICT' file.
• If your program will run only on Macintoshes with 128K ROMs (or ROMs
produced after those), you can store a large 'PICT' in a resource. In those
ROMs, QuickDraw reads the 'PICT' until it reaches the end-of- picture
opcode and ignores the size word at the beginning of the 'PICT'. Remember,
if you put large PICTs in resources, your program won't run on
Macintoshes with 64K ROMs.
Example
/*replacement for the QuickDraw bottleneck routine*/
pascal void GetPICTData ( Ptr dataPtr, short byteCount)
{ /* GetPICTData */
OSErr err;
long longCount;
longCount = byteCount;
err = FSRead( globalRef,&longCount,dataPtr);
/*can't check for an error because we don't know how to handle it*/
} /* GetPICTData */
/*error code if DrawPicture aborted*/
# define abortPICT 128
OSErr GetDrawPICTFile() /*read in a 'PICT' selected by the user*/
{ /* GetDrawPICTFile */
Point wher; /*where to display dialog*/
SFReply reply; /*reply record*/
SFTypeList myFileTypes; /*see Standard File */
short numFileTypes;
OSErr err;
QDProcsPtr savedProcs;
QDProcs myProcs; /*use CQDProcs for a color window*/
PicHandle myPicture;
/*we need a picture handle for DrawPicture*/
long longCount,myEOF,filePos;
wher.h = 20;
wher.v = 20;
numFileTypes = 1; /*display 'PICT's*/
myFileTypes[0] = 'PICT';
SFGetFile(wher,'',nil,numFileTypes,myFileTypes,nil,&reply);
if (reply.good)
{
SetStdProcs(&myProcs);
/*use SetStdCProcs for a CGrafPort*/
myProcs.getPicProc = GetPICTData;
savedProcs = thePort->grafProcs;
/*set the grafProcs to ours*/
thePort->grafProcs = &myProcs;
myPicture = (PicHandle)NewHandle(sizeof(Picture));
err = FSOpen(&reply.fName,reply. vRefNum,& globalRef);
if (err != noErr) return err;
err = GetEOF( globalRef,&myEOF);
/*get EOF for later check*/
if (err != noErr) return err;
err = SetFPos( globalRef,fsFromStart,512);/*skip header*/
if (err != noErr) return err;
/*read in the (obsolete) size word and the picFrame*/
longCount = sizeof(Picture);
err = FSRead( globalRef,&longCount,(Ptr)*myPicture);
if (err != noErr) return err;
DrawPicture(myPicture,&(**myPicture).picFrame);
/*draw the picture*/
err = GetFPos( globalRef,&filePos); /*get position for check*/
if (err != noErr) return err;
err = FSClose( globalRef);
if (err != noErr) return err;
DisposHandle((Handle)myPicture);
thePort->grafProcs = savedProcs; /*restore the procs*/
/*Check for errors. if there wasn't enough room,*/
/*DrawPicture will abort; the FILE position mark*/
/*won't be at the end of the FILE.*/
if (filePos != myEOF) return abortPICT;
else return noErr;
} /*if (reply.good) */
} /* GetDrawPICTFile */
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