OSStatus
TextViewSetBGAlpha( HIViewRef textView, float alpha )
{
OSStatus status = paramErr;
SInt32 unused;
CGColorRef prevColor = NULL;
CGColorRef newColor = NULL;
status = HITextViewCopyBackgroundColor( textView, &prevColor );
require_noerr( status, FAIL );
// make a new copy with alpha
newColor = CGColorCreateCopyWithAlpha( prevColor, alpha );
require_action( newColor != NULL, FAIL, status = paramErr );
// reset the new color with alpha
status = HITextViewSetBackgroundColor( textView, newColor );
if( newColor != NULL )
CGColorRelease( newColor );
FAIL:
return status;
}
void drawWithColorRefs(CGContextRef context)
{
static CGColorRef opaqueRedColor = NULL, opaqueBlueColor = NULL, transparentBlueColor = NULL;
// Initialize the CGColorRefs if necessary
if(opaqueRedColor == NULL){
// Initialize the color array to an opaque red
// in the generic calibrated RGB color space.
float color[4] = { 0.663, 0.0, 0.031, 1.0 };
CGColorSpaceRef theColorSpace = getTheCalibratedRGBColorSpace();
// Create a CGColorRef for opaque red.
opaqueRedColor = CGColorCreate(theColorSpace, color);
// Make the color array correspond to an opaque blue color.
color[0] = 0.482; color[1] = 0.62; color[2] = 0.871;
// Create another CGColorRef for opaque blue.
opaqueBlueColor = CGColorCreate(theColorSpace, color);
// Create a new CGColorRef from the opaqueBlue CGColorRef
// but with a different alpha value.
transparentBlueColor = CGColorCreateCopyWithAlpha(opaqueBlueColor, 0.5);
if(!(opaqueRedColor && opaqueBlueColor && transparentBlueColor)){
fprintf(stderr, "Couldn't create one of the CGColorRefs!!!\n");
return;
}
}
// Set the fill color to the opaque red CGColor object.
CGContextSetFillColorWithColor(context, opaqueRedColor);
// Set the stroke color to the opaque blue CGColor object.
CGContextSetStrokeColorWithColor(context, opaqueBlueColor);
CGContextSetLineWidth(context, 8.);
// Draw the first rectangle.
CGContextBeginPath(context);
CGContextAddRect(context, CGRectMake(20., 20., 100., 100.));
CGContextDrawPath(context, kCGPathFillStroke);
// Set the stroke color to be that of the transparent blue
// CGColor object.
CGContextSetStrokeColorWithColor(context, transparentBlueColor);
// Draw a second rectangle to the right of the first one.
CGContextBeginPath(context);
CGContextAddRect(context, CGRectMake(140., 20., 100., 100.));
CGContextDrawPath(context, kCGPathFillStroke);
}
//---------------------------------------------------------------------
// Sets the alpha of an HITextView to the specified value
//
OSStatus TextViewSetAlpha(HIViewRef textView, float alpha)
{
CGColorRef prevColor, newColor;
OSStatus status;
status = HITextViewCopyBackgroundColor(textView, &prevColor);
require_noerr( status, CantGetBackgroundColor );
newColor = CGColorCreateCopyWithAlpha(prevColor, alpha);
require( (newColor != NULL), CantCreateNewColor );
status = HITextViewSetBackgroundColor(textView, newColor);
check_noerr( status );
CGColorRelease(newColor);
CantCreateNewColor:
CGColorRelease(prevColor);
CantGetBackgroundColor:
return status;
}
