/*

File: ShadeRect.c

Version: 1.0

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*/

#include <Carbon/Carbon.h>

#include "ShadeRect.h"

// -----------------------------------------------------------------------------

// types

// -----------------------------------------------------------------------------

//

typedef struct

{

float start;

float range;

} ShadeData;

typedef struct

{

CGRGB start;

CGRGB range;

} ColorShadeData;

// -----------------------------------------------------------------------------

// prototypes

// -----------------------------------------------------------------------------

//

void GrayscaleGradientEvaluate(

void* info,

const float* in,

float* out );

void ColorGradientEvaluate(

void* info,

const float* in,

float* out );

// -----------------------------------------------------------------------------

// GrayscaleGradientEvaluate

// -----------------------------------------------------------------------------

//

void GrayscaleGradientEvaluate(

void* inInfo,

const float* in,

float* out )

{

ShadeData* data = (ShadeData*) inInfo;

out[ 0 ] = out[ 1 ] = out[ 2 ] = data->start + in[ 0 ] * data->range;

// always 100% alpha CGShading alpha isn't working in Jaguar right now

// anyway, so if it does start working, the behavior won't change.

out[ 3 ] = 1;

}

// -----------------------------------------------------------------------------

// ShadeRect

// -----------------------------------------------------------------------------

//

OSStatus ShadeRect(

CGContextRef inContext )

{

OSStatus err = noErr;

CGColorSpaceRef colorSpace;

CGFunctionCallbacks callbacks = { 0, GrayscaleGradientEvaluate, NULL };

CGFunctionRef function;

CGShadingRef shading;

ShadeData data;

// Warning: this stuff is sitting on the stack. Be careful if you move

// the shading code around.

data.start = inStartShade;

data.range = inEndShade - inStartShade;

CGContextSaveGState( inContext );

CGContextClipToRect( inContext, *inRect );

colorSpace = CGColorSpaceCreateDeviceRGB();

require_action( colorSpace != NULL, CantCreateColorSpace, err = memFullErr );

function = CGFunctionCreate(

&data, // info

1, // domainDimension

NULL, // input domain NULL == no range clipping

4, // rangeDimension,

NULL, // output domain NULL == no range clipping

&callbacks ); // CGFunctionCallbacks

require_action( function != NULL, CantCreateFunction, err = memFullErr );

shading = CGShadingCreateAxial(

colorSpace,

inRect->origin, // start

CGPointMake( CGRectGetMinX( *inRect ), CGRectGetMaxY( *inRect ) ), // end

function,

false, // extendStart

false ); // extendEnd

require_action( colorSpace != NULL, CantCreateShading, err = memFullErr );

CGContextDrawShading( inContext, shading);

CantCreateFunction:

CGShadingRelease( shading );

CantCreateShading:

CGColorSpaceRelease( colorSpace );

CantCreateColorSpace:

CGContextRestoreGState( inContext );

return err;

}

// -----------------------------------------------------------------------------

// ColorGradientEvaluate

// -----------------------------------------------------------------------------

//

void ColorGradientEvaluate(

void* inInfo,

const float* in,

float* out )

{

ColorShadeData* data = (ColorShadeData*) inInfo;

out[ 0 ] = data->start.red + in[ 0 ] * data->range.red;

out[ 1 ] = data->start.green + in[ 0 ] * data->range.green;

out[ 2 ] = data->start.blue + in[ 0 ] * data->range.blue;

// always 100% alpha CGShading alpha isn't working in Jaguar right now

// anyway, so if it does start working, the behavior won't change.

out[ 3 ] = 1;

}

// -----------------------------------------------------------------------------

// ShadeRectColor

// -----------------------------------------------------------------------------

//

OSStatus ShadeRectColor(

CGContextRef inContext )

{

OSStatus err = noErr;

CGColorSpaceRef colorSpace;

CGFunctionCallbacks callbacks = { 0, ColorGradientEvaluate, NULL };

CGFunctionRef function;

CGShadingRef shading;

ColorShadeData data;

// Warning: this stuff is sitting on the stack. Be careful if you move

// the shading code around.

data.start = *inStartColor;

data.range.red = inEndColor->red - inStartColor->red;

data.range.green = inEndColor->green - inStartColor->green;

data.range.blue = inEndColor->blue - inStartColor->blue;

CGContextSaveGState( inContext );

CGContextClipToRect( inContext, *inRect );

colorSpace = CGColorSpaceCreateDeviceRGB();

require_action( colorSpace != NULL, CantCreateColorSpace, err = memFullErr );

function = CGFunctionCreate(

&data, // info

1, // domainDimension

NULL, // input domain NULL == no range clipping

4, // rangeDimension,

NULL, // output domain NULL == no range clipping

&callbacks ); // CGFunctionCallbacks

require_action( function != NULL, CantCreateFunction, err = memFullErr );

shading = CGShadingCreateAxial(

colorSpace,

inRect->origin, // start

CGPointMake( CGRectGetMinX( *inRect ), CGRectGetMaxY( *inRect ) ), // end

function,

false, // extendStart

false ); // extendEnd

require_action( colorSpace != NULL, CantCreateShading, err = memFullErr );

CGContextDrawShading( inContext, shading);

CantCreateFunction:

CGShadingRelease( shading );

CantCreateShading:

CGColorSpaceRelease( colorSpace );

CantCreateColorSpace:

CGContextRestoreGState( inContext );

return err;

}