/*
 * Copyright 2005, Stephan Aßmus <superstippi@gmx.de>. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * DrawingMode implementing B_OP_ALPHA in "Constant Composite" mode on B_RGBA32.
 *
 */

#ifndef DRAWING_MODE_ALPHA_CC_H
#define DRAWING_MODE_ALPHA_CC_H

#include "DrawingMode.h"

// BLEND_ALPHA_CC
#define BLEND_ALPHA_CC(d, r, g, b, a) \
{ \
        BLEND_COMPOSITE16(d, r, g, b, a); \
}

// ASSIGN_ALPHA_CC
#define ASSIGN_ALPHA_CC(d, r, g, b) \
{ \
        d[0] = (b); \
        d[1] = (g); \
        d[2] = (r); \
        d[3] = 255; \
}

// blend_pixel_alpha_cc
void
blend_pixel_alpha_cc(int x, int y, const color_type& c, uint8 cover,
                                         agg_buffer* buffer, const PatternHandler* pattern)
{
        uint8* p = buffer->row_ptr(y) + (x << 2);
        rgb_color color = pattern->ColorAt(x, y);
        uint16 alpha = pattern->HighColor().alpha * cover;
        if (alpha == 255 * 255) {
                ASSIGN_ALPHA_CC(p, color.red, color.green, color.blue);
        } else {
                BLEND_ALPHA_CC(p, color.red, color.green, color.blue, alpha);
        }
}

// blend_hline_alpha_cc
void
blend_hline_alpha_cc(int x, int y, unsigned len, 
                                         const color_type& c, uint8 cover,
                                         agg_buffer* buffer, const PatternHandler* pattern)
{
        rgb_color color = pattern->HighColor();
        uint16 alpha = color.alpha * cover;
        if (alpha == 255 * 255) {
                // cache the low and high color as 32bit values
                // high color
                uint32 vh;
                uint8* p8 = (uint8*)&vh;
                p8[0] = color.blue;
                p8[1] = color.green;
                p8[2] = color.red;
                p8[3] = 255;
                // low color
                color = pattern->LowColor();
                uint32 vl;
                p8 = (uint8*)&vl;
                p8[0] = color.blue;
                p8[1] = color.green;
                p8[2] = color.red;
                p8[3] = 255;
                // row offset as 32 bit pointer
                uint32* p32 = (uint32*)(buffer->row_ptr(y)) + x;
                do {
                        if (pattern->IsHighColor(x, y))
                                *p32 = vh;
                        else
                                *p32 = vl;
                        p32++;
                        x++;
                } while(--len);
        } else {
                uint8* p = buffer->row_ptr(y) + (x << 2);
                do {
                        rgb_color color = pattern->ColorAt(x, y);
                        BLEND_ALPHA_CC(p, color.red, color.green, color.blue, alpha);
                        x++;
                        p += 4;
                } while(--len);
        }
}

// blend_solid_hspan_alpha_cc
void
blend_solid_hspan_alpha_cc(int x, int y, unsigned len, 
                                                   const color_type& c, const uint8* covers,
                                                   agg_buffer* buffer, const PatternHandler* pattern)
{
        uint8* p = buffer->row_ptr(y) + (x << 2);
        uint8 hAlpha = pattern->HighColor().alpha;
        do {
                rgb_color color = pattern->ColorAt(x, y);
                uint16 alpha = hAlpha * *covers;
                if (alpha) {
                        if (alpha == 255 * 255) {
                                ASSIGN_ALPHA_CC(p, color.red, color.green, color.blue);
                        } else {
                                BLEND_ALPHA_CC(p, color.red, color.green, color.blue, alpha);
                        }
                }
                covers++;
                p += 4;
                x++;
        } while(--len);
}

// blend_solid_vspan_alpha_cc
void
blend_solid_vspan_alpha_cc(int x, int y, unsigned len, 
                                                   const color_type& c, const uint8* covers,
                                                   agg_buffer* buffer, const PatternHandler* pattern)
{
        uint8* p = buffer->row_ptr(y) + (x << 2);
        uint8 hAlpha = pattern->HighColor().alpha;
        do {
                rgb_color color = pattern->ColorAt(x, y);
                uint16 alpha = hAlpha * *covers;
                if (alpha) {
                        if (alpha == 255 * 255) {
                                ASSIGN_ALPHA_CC(p, color.red, color.green, color.blue);
                        } else {
                                BLEND_ALPHA_CC(p, color.red, color.green, color.blue, alpha);
                        }
                }
                covers++;
                p += buffer->stride();
                y++;
        } while(--len);
}


// blend_color_hspan_alpha_cc
void
blend_color_hspan_alpha_cc(int x, int y, unsigned len, 
                                                   const color_type* colors, 
                                                   const uint8* covers, uint8 cover,
                                                   agg_buffer* buffer, const PatternHandler* pattern)
{
        uint8* p = buffer->row_ptr(y) + (x << 2);
        uint8 hAlpha = pattern->HighColor().alpha;
        if (covers) {
                // non-solid opacity
                do {
                        uint16 alpha = hAlpha * colors->a * *covers / 255;
                        if (alpha) {
                                if (alpha == 255 * 255) {
                                        ASSIGN_ALPHA_CC(p, colors->r, colors->g, colors->b);
                                } else {
                                        BLEND_ALPHA_CC(p, colors->r, colors->g, colors->b, alpha);
                                }
                        }
                        covers++;
                        p += 4;
                        ++colors;
                } while(--len);
        } else {
                // solid full opcacity
                uint16 alpha = hAlpha * colors->a * cover / 255;
                if (alpha == 255 * 255) {
                        do {
                                ASSIGN_ALPHA_CC(p, colors->r, colors->g, colors->b);
                                p += 4;
                                ++colors;
                        } while(--len);
                // solid partial opacity
                } else if (alpha) {
                        do {
                                BLEND_ALPHA_CC(p, colors->r, colors->g, colors->b, alpha);
                                p += 4;
                                ++colors;
                        } while(--len);
                }
        }
}

#endif // DRAWING_MODE_ALPHA_CC_H