void doIndexedColorDrawGraphics(CGContextRef context)
{
CGColorSpaceRef theBaseRGBSpace = getTheCalibratedRGBColorSpace();
CGColorSpaceRef theIndexedSpace = NULL;
unsigned char lookupTable[6];
float opaqueRed[] = { 0, 1 }; // index, alpha
float aBlue[] = { 1, 1 }; // index, alpha
// Set the first 3 values in the lookup table to a red of
// 169/255 = 0.663, no green, and blue = 8/255 = 0.031. This makes
// the first entry in the lookup table a shade of red.
lookupTable[0] = 169; lookupTable[1] = 0; lookupTable[2] = 8;
// Set the second 3 values in the lookup table to a red value
// of 123/255 = 0.482, a green value of 158/255 = 0.62, and
// a blue value of 222/255 = 0.871. This makes the second entry
// in the lookup table a shade of blue.
lookupTable[3] = 123; lookupTable[4] = 158; lookupTable[5] = 222;
// Create the indexed color space with this color lookup table,
// using the RGB color space as the base color space and a 2 element
// color lookup table to characterize the indexed color space.
theIndexedSpace = CGColorSpaceCreateIndexed(theBaseRGBSpace, 1, lookupTable);
if(theIndexedSpace != NULL){
CGContextSetStrokeColorSpace(context, theIndexedSpace);
CGContextSetFillColorSpace(context, theIndexedSpace);
// Release the color space this code created since it is no
// longer needed in this routine.
CGColorSpaceRelease(theIndexedSpace);
// Set the stroke color to an opaque blue.
CGContextSetStrokeColor(context, aBlue);
// Set the fill color to an opaque red.
CGContextSetFillColor(context, opaqueRed);
CGContextSetLineWidth(context, 8.);
// Draw the first rectangle.
CGContextBeginPath(context);
CGContextAddRect(context, CGRectMake(20., 20., 100., 100.));
CGContextDrawPath(context, kCGPathFillStroke);
// Continue to use the stroke colorspace already set
// but change the stroke alpha value to a semitransparent value
// while leaving the index value unchanged.
aBlue[1] = 0.5;
CGContextSetStrokeColor(context, aBlue);
// Draw another rectangle to the right of the first one.
CGContextBeginPath(context);
CGContextAddRect(context, CGRectMake(140., 20., 100., 100.));
CGContextDrawPath(context, kCGPathFillStroke);
}else
fprintf(stderr, "Couldn't make the indexed color space!\n");
}
CGColorSpaceRef colorSpaceFromPDFArray(CGPDFArrayRef colorSpaceArray){
CGColorSpaceRef cgColorSpace = NULL, alternateColorSpace = NULL;
CGPDFStreamRef stream;
const char *colorSpaceName = NULL, *alternateColorSpaceName = NULL;
CGPDFInteger numberOfComponents;
CGPDFDictionaryRef dict;
bool retrieved;
CGFloat *range;
CGPDFArrayRef rangeArray;
if (CGPDFArrayGetName(colorSpaceArray, 0, &colorSpaceName)) {
if (strcmp(colorSpaceName, "ICCBased") == 0) {
if (CGPDFArrayGetStream(colorSpaceArray, 1, &stream)) {
dict = CGPDFStreamGetDictionary(stream);
// First obtain the alternate color space if present
if (CGPDFDictionaryGetName(dict, "Alternate", &alternateColorSpaceName)) {
if (strcmp(alternateColorSpaceName, "DeviceRGB") == 0) {
alternateColorSpace = CGColorSpaceCreateDeviceRGB();
} else if (strcmp(alternateColorSpaceName, "DeviceGray") ==
0) {
alternateColorSpace = CGColorSpaceCreateDeviceGray();
} else if (strcmp(alternateColorSpaceName, "DeviceCMYK") ==
0) {
alternateColorSpace = CGColorSpaceCreateDeviceCMYK();
}
}
// Obtain the preferential color space
CGPDFDataFormat dataFormat;
CFDataRef colorSpaceDataPtr =
CGPDFStreamCopyData(stream, &dataFormat);
if (dataFormat == CGPDFDataFormatRaw) {
CGDataProviderRef profile =
CGDataProviderCreateWithCFData(colorSpaceDataPtr);
retrieved = CGPDFDictionaryGetInteger(dict, "N",
&numberOfComponents);
// Deduce an alternate color space if we don't have one
//already
if (alternateColorSpace == NULL) {
switch (numberOfComponents) {
case 1:
alternateColorSpace = CGColorSpaceCreateDeviceGray();
break;
case 3:
alternateColorSpace = CGColorSpaceCreateDeviceRGB();
break;
case 4:
alternateColorSpace = CGColorSpaceCreateDeviceCMYK();
break;
default:
break;
}
}
range = malloc(numberOfComponents * 2 * sizeof(CGFloat));
if (!CGPDFDictionaryGetArray(dict, "Range", &rangeArray)) {
int i = 0;
for (; i < numberOfComponents * 2; i += 2) {
range[i] = (i % 2 == 0) ? 0.0 : 1.0;
}
} else {
size_t count = CGPDFArrayGetCount(rangeArray);
int i = 0;
for (; i < count; i++) {
(void)CGPDFArrayGetNumber(rangeArray, i, &range[i]);
}
}
cgColorSpace = CGColorSpaceCreateICCBased(numberOfComponents, range, profile,
alternateColorSpace);
CGDataProviderRelease(profile);
free(range);
if (cgColorSpace) {
// Since we have a preferential color space, we no
//longer need the hang on to the alternate color space
CGColorSpaceRelease(alternateColorSpace);
} else {
cgColorSpace = alternateColorSpace;
}
} else if (dataFormat == CGPDFDataFormatJPEGEncoded) {
//
} else if (dataFormat == CGPDFDataFormatJPEG2000) {
//
}
}
} else if (strcmp(colorSpaceName, "Indexed") == 0) {
CGColorSpaceRef baseSpace;
CGPDFArrayRef base = NULL;
CGPDFInteger highValue = 0;
CGPDFStreamRef stream = NULL;
CGPDFStringRef string;
const unsigned char *chars;
const char *namedColorSpaceName;
if (CGPDFArrayGetArray(colorSpaceArray, 1, &base)) {
baseSpace = colorSpaceFromPDFArray(base);
} else if (CGPDFArrayGetName(colorSpaceArray, 1,
&namedColorSpaceName)) {
if (strcmp(namedColorSpaceName, "DeviceRGB") == 0) {
baseSpace = CGColorSpaceCreateDeviceRGB();
} else if (strcmp(namedColorSpaceName, "DeviceGray") == 0) {
baseSpace = CGColorSpaceCreateDeviceGray();
} else if (strcmp(namedColorSpaceName, "DeviceCMYK") == 0) {
baseSpace = CGColorSpaceCreateDeviceCMYK();
}
}
retrieved = CGPDFArrayGetInteger(colorSpaceArray, 2, &highValue);
if (CGPDFArrayGetStream(colorSpaceArray, 3, &stream)) {
chars = CFDataGetBytePtr(CGPDFStreamCopyData(stream, NULL));
} else if (CGPDFArrayGetString(colorSpaceArray, 3, &string)) {
chars = CGPDFStringGetBytePtr(string);
} else {
// TODO: Raise some error state?
}
cgColorSpace = CGColorSpaceCreateIndexed(baseSpace, highValue,
chars);
}
}
return (CGColorSpaceRef)CFMakeCollectable(cgColorSpace);
}
CGColorSpaceRef CGColorSpaceCreateIndexed_wrap(CGColorSpaceRef base, u_char* table, uint32 len ) {
return CGColorSpaceCreateIndexed(base, len, table);
}
