darling-cocotron/Onyx2D/O2argb8u.h

#import <Foundation/NSObject.h>
#import <Onyx2D/O2Geometry.h>
#import <Onyx2D/VGmath.h>

typedef struct {
   uint8_t a;
   uint8_t r;
   uint8_t g;
   uint8_t b;
} O2argb8u_BE;

typedef struct {
   uint8_t b;
   uint8_t g;
   uint8_t r;
   uint8_t a;
} O2argb8u_LE;

typedef struct {
   uint8_t r;
   uint8_t g;
   uint8_t b;
   uint8_t a;
} O2rgba8u_BE;

#ifdef __LITTLE_ENDIAN__
typedef O2argb8u_LE O2argb8u;
#endif
#ifdef __BIG_ENDIAN__
typedef O2argb8u_BE O2argb8u;
#endif

#define COVERAGE_MULTIPLIER 256

static inline uint32_t inverseCoverage(uint32_t coverage){
   return COVERAGE_MULTIPLIER-coverage;
}

static inline uint32_t multiplyByCoverage(uint32_t value,uint32_t coverage){
   return (value*coverage)/COVERAGE_MULTIPLIER;
}


static inline uint32_t O2Image_16u_div_255(uint32_t t){
// t/255
// From Imaging Compositing Fundamentals, Technical Memo 4 by Alvy Ray Smith, Aug 15, 1995
// Faster and more accurate in that it rounds instead of truncates
// Perfectly accurate for 8 and 16 bit values
// (loses a small amount of precision for >16 bits values)
   t = t + 0x80;
   t= ( ( ( (t)>>8 ) + (t) )>>8 );
   
   return t;
}

static inline uint8_t O2Image_8u_mul_8u_div_255(uint8_t c,uint8_t a){
   return O2Image_16u_div_255(c*a);
}

static inline uint16_t O2Image_16u_mul_8u_div_255(uint16_t c,uint8_t a){
   return O2Image_16u_div_255(c*a);
}

ONYX2D_STATIC_INLINE uint32_t Mul8x2(uint32_t pair,uint32_t alpha){
    const uint32_t rbmask=0x00FF00FF;
	pair &= rbmask;
	uint32_t i = alpha * pair + 0x800080;
	return (i + ((i >> 8) & rbmask)) >> 8 & rbmask;
}

static inline O2argb8u O2argb8uMultiplyByMask8u(O2argb8u result,uint32_t value){
   result.r=O2Image_8u_mul_8u_div_255(result.r,value);
   result.g=O2Image_8u_mul_8u_div_255(result.g,value);
   result.b=O2Image_8u_mul_8u_div_255(result.b,value);
   result.a=O2Image_8u_mul_8u_div_255(result.a,value);

   return result;
}

static inline O2argb8u O2argb8uMultiplyByCoverageNoBypass(O2argb8u result,unsigned value){
   result.r=multiplyByCoverage(result.r,value);
   result.g=multiplyByCoverage(result.g,value);
   result.b=multiplyByCoverage(result.b,value);
   result.a=multiplyByCoverage(result.a,value);

   return result;
   }

static inline O2argb8u O2argb8uMultiplyByCoverage(O2argb8u result,unsigned value){
   if(value!=COVERAGE_MULTIPLIER)
    result=O2argb8uMultiplyByCoverageNoBypass(result,value);

   return result;
}

static inline O2argb8u O2argb8uMultiplyByCoverageAdd(O2argb8u left,uint32_t leftCoverage,O2argb8u right,uint32_t rightCoverage){
   uint32_t srb=*(uint32_t *)&left;
   uint32_t sag=srb>>8;
   
   sag&=0x00FF00FF;
   srb&=0x00FF00FF;
   sag=((sag*leftCoverage)>>8)&0x00FF00FF;
   srb=((srb*leftCoverage)>>8)&0x00FF00FF;

   uint32_t drb=*(uint32_t *)&right;
   uint32_t dag=drb>>8;
    
   dag&=0x00FF00FF;
   drb&=0x00FF00FF;
        
   dag=((dag*rightCoverage)>>8)&0x00FF00FF;
   drb=((drb*rightCoverage)>>8)&0x00FF00FF;
   
   uint32_t r;
   
   sag+=dag;
   r=RI_INT_MIN(sag,0x00FF0000)<<8;
   r|=RI_INT_MIN(sag&0xFFFF,255)<<8;
   srb+=drb;
   r|=RI_INT_MIN(srb,0x00FF0000);
   r|=RI_INT_MIN(srb&0xFFFF,255);

   return *(O2argb8u *)&r;
}

static inline O2argb8u O2argb8uAdd(O2argb8u result,O2argb8u other){
   result.r=RI_INT_MIN((unsigned)result.r+(unsigned)other.r,255);
   result.g=RI_INT_MIN((unsigned)result.g+(unsigned)other.g,255);
   result.b=RI_INT_MIN((unsigned)result.b+(unsigned)other.b,255);
   result.a=RI_INT_MIN((unsigned)result.a+(unsigned)other.a,255);
   return result;
}


void O2ApplyCoverageAndMaskToSpan_largb8u_PRE(O2argb8u *dst,uint32_t icoverage,uint8_t *mask,O2argb8u *src,int length);

void O2ApplyCoverageToSpan_largb8u_PRE(O2argb8u *dst,int coverage,O2argb8u *src,int length);


void O2argb8u_sover_by_coverage(O2argb8u *src,O2argb8u *dst,unsigned coverage,int length);

 void O2argb8u_copy_by_coverage(O2argb8u *src,O2argb8u *dst,unsigned coverage,int length);

 void O2BlendSpanNormal_8888(O2argb8u *src,O2argb8u *dst,int length);

 void O2BlendSpanClear_8888(O2argb8u *src,O2argb8u *dst,int length);

 void O2BlendSpanCopy_8888(O2argb8u *src,O2argb8u *dst,int length);

 void O2BlendSpanSourceIn_8888(O2argb8u *src,O2argb8u *dst,int length);
 void O2BlendSpanXOR_8888(O2argb8u *src,O2argb8u *dst,int length);
 void O2BlendSpanPlusLighter_8888(O2argb8u *src,O2argb8u *dst,int length);