path: root/src/libply-splash-core/ply-pixel-buffer.c

/* ply-pixel-buffer.c - pixelbuffer abstraction
 *
 * Copyright (C) 2006, 2007, 2008, 2009 Red Hat, Inc.
 *               2008 Charlie Brej <cbrej@cs.man.ac.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * Written by: Charlie Brej <cbrej@cs.man.ac.uk>
 *             Kristian Høgsberg <krh@redhat.com>
 *             Ray Strode <rstrode@redhat.com>
 */
#include "config.h"
#include "ply-list.h"
#include "ply-pixel-buffer.h"
#include "ply-logger.h"

#include <assert.h>
#include <errno.h>
#include <math.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define ALPHA_MASK 0xff000000

struct _ply_pixel_buffer
{
        uint32_t       *bytes;

        ply_rectangle_t area;
        ply_list_t     *clip_areas;

        ply_region_t   *updated_areas;
        uint32_t        is_opaque : 1;
};

static inline void ply_pixel_buffer_blend_value_at_pixel (ply_pixel_buffer_t *buffer,
                                                          int                 x,
                                                          int                 y,
                                                          uint32_t            pixel_value);

static void ply_pixel_buffer_fill_area_with_pixel_value (ply_pixel_buffer_t *buffer,
                                                         ply_rectangle_t    *fill_area,
                                                         uint32_t            pixel_value);

__attribute__((__pure__))
static inline uint32_t
blend_two_pixel_values (uint32_t pixel_value_1,
                        uint32_t pixel_value_2)
{
        if ((pixel_value_2 & 0xff000000) == 0xff000000) {
                uint8_t alpha_1, red_1, green_1, blue_1;
                uint8_t red_2, green_2, blue_2;
                uint_least32_t red, green, blue;

                alpha_1 = (uint8_t) (pixel_value_1 >> 24);
                red_1 = (uint8_t) (pixel_value_1 >> 16);
                green_1 = (uint8_t) (pixel_value_1 >> 8);
                blue_1 = (uint8_t) pixel_value_1;

                red_2 = (uint8_t) (pixel_value_2 >> 16);
                green_2 = (uint8_t) (pixel_value_2 >> 8);
                blue_2 = (uint8_t) pixel_value_2;

                red = red_1 * 255 + red_2 * (255 - alpha_1);
                green = green_1 * 255 + green_2 * (255 - alpha_1);
                blue = blue_1 * 255 + blue_2 * (255 - alpha_1);

                red = (uint8_t) ((red + (red >> 8) + 0x80) >> 8);
                green = (uint8_t) ((green + (green >> 8) + 0x80) >> 8);
                blue = (uint8_t) ((blue + (blue >> 8) + 0x80) >> 8);

                return 0xff000000 | (red << 16) | (green << 8) | blue;
        } else {
                uint8_t alpha_1, red_1, green_1, blue_1;
                uint8_t alpha_2, red_2, green_2, blue_2;
                uint_least32_t alpha, red, green, blue;

                alpha_1 = (uint8_t) (pixel_value_1 >> 24);
                red_1 = (uint8_t) (pixel_value_1 >> 16);
                green_1 = (uint8_t) (pixel_value_1 >> 8);
                blue_1 = (uint8_t) pixel_value_1;

                alpha_2 = (uint8_t) (pixel_value_2 >> 24);
                red_2 = (uint8_t) (pixel_value_2 >> 16);
                green_2 = (uint8_t) (pixel_value_2 >> 8);
                blue_2 = (uint8_t) pixel_value_2;

                red = red_1 * alpha_1 + red_2 * alpha_2 * (255 - alpha_1);
                green = green_1 * alpha_1 + green_2 * alpha_2 * (255 - alpha_1);
                blue = blue_1 * alpha_1 + blue_2 * alpha_2 * (255 - alpha_1);
                alpha = alpha_1 * 255 + alpha_2 * (255 - alpha_1);

                red = (red + (red >> 8) + 0x80) >> 8;
                red = MIN (red, 0xff);

                green = (green + (green >> 8) + 0x80) >> 8;
                green = MIN (green, 0xff);

                blue = (blue + (blue >> 8) + 0x80) >> 8;
                blue = MIN (blue, 0xff);

                alpha = (alpha + (alpha >> 8) + 0x80) >> 8;
                alpha = MIN (alpha, 0xff);

                return (alpha << 24) | (red << 16) | (green << 8) | blue;
        }
}

__attribute__((__pure__))
static inline uint32_t
make_pixel_value_translucent (uint32_t pixel_value,
                              uint8_t  opacity)
{
        uint_least16_t alpha, red, green, blue;

        if (opacity == 255)
                return pixel_value;

        alpha = (uint8_t) (pixel_value >> 24);
        red = (uint8_t) (pixel_value >> 16);
        green = (uint8_t) (pixel_value >> 8);
        blue = (uint8_t) pixel_value;

        red *= opacity;
        green *= opacity;
        blue *= opacity;
        alpha *= opacity;

        red = (uint8_t) ((red + (red >> 8) + 0x80) >> 8);
        green = (uint8_t) ((green + (green >> 8) + 0x80) >> 8);
        blue = (uint8_t) ((blue + (blue >> 8) + 0x80) >> 8);
        alpha = (uint8_t) ((alpha + (alpha >> 8) + 0x80) >> 8);

        return (alpha << 24) | (red << 16) | (green << 8) | blue;
}

static inline void
ply_pixel_buffer_blend_value_at_pixel (ply_pixel_buffer_t *buffer,
                                       int                 x,
                                       int                 y,
                                       uint32_t            pixel_value)
{
        uint32_t old_pixel_value;

        if ((pixel_value >> 24) != 0xff) {
                old_pixel_value = buffer->bytes[y * buffer->area.width + x];

                pixel_value = blend_two_pixel_values (pixel_value, old_pixel_value);
        }

        buffer->bytes[y * buffer->area.width + x] = pixel_value;
}

static void
ply_pixel_buffer_crop_area_to_clip_area (ply_pixel_buffer_t *buffer,
                                         ply_rectangle_t    *area,
                                         ply_rectangle_t    *cropped_area)
{
        ply_list_node_t *node;

        *cropped_area = *area;

        node = ply_list_get_first_node (buffer->clip_areas);
        while (node != NULL) {
                ply_list_node_t *next_node;
                ply_rectangle_t *clip_rectangle;

                clip_rectangle = ply_list_node_get_data (node);
                next_node = ply_list_get_next_node (buffer->clip_areas, node);

                ply_rectangle_intersect (cropped_area, clip_rectangle, cropped_area);

                node = next_node;
        }
}

static void
ply_pixel_buffer_fill_area_with_pixel_value (ply_pixel_buffer_t *buffer,
                                             ply_rectangle_t    *fill_area,
                                             uint32_t            pixel_value)
{
        unsigned long row, column;
        ply_rectangle_t cropped_area;

        ply_pixel_buffer_crop_area_to_clip_area (buffer, fill_area, &cropped_area);

        /* If we're filling the entire buffer with a fully opaque color,
         * then make note of it
         */
        if (fill_area == &buffer->area &&
            (pixel_value >> 24) == 0xff) {
                buffer->is_opaque = true;
        }

        for (row = cropped_area.y; row < cropped_area.y + cropped_area.height; row++) {
                for (column = cropped_area.x; column < cropped_area.x + cropped_area.width; column++) {
                        ply_pixel_buffer_blend_value_at_pixel (buffer,
                                                               column, row,
                                                               pixel_value);
                }
        }
}

void
ply_pixel_buffer_push_clip_area (ply_pixel_buffer_t *buffer,
                                 ply_rectangle_t    *clip_area)
{
        ply_rectangle_t *new_clip_area;

        new_clip_area = malloc (sizeof(*new_clip_area));

        *new_clip_area = *clip_area;
        ply_list_append_data (buffer->clip_areas, new_clip_area);
}

void
ply_pixel_buffer_pop_clip_area (ply_pixel_buffer_t *buffer)
{
        ply_list_node_t *last_node;

        last_node = ply_list_get_last_node (buffer->clip_areas);
        free (ply_list_node_get_data (last_node));
        ply_list_remove_node (buffer->clip_areas, last_node);
}

ply_pixel_buffer_t *
ply_pixel_buffer_new (unsigned long width,
                      unsigned long height)
{
        ply_pixel_buffer_t *buffer;

        buffer = calloc (1, sizeof(ply_pixel_buffer_t));

        buffer->updated_areas = ply_region_new ();
        buffer->bytes = (uint32_t *) calloc (height, width * sizeof(uint32_t));
        buffer->area.width = width;
        buffer->area.height = height;

        buffer->clip_areas = ply_list_new ();
        ply_pixel_buffer_push_clip_area (buffer, &buffer->area);
        buffer->is_opaque = false;

        return buffer;
}

static void
free_clip_areas (ply_pixel_buffer_t *buffer)
{
        while (ply_list_get_length (buffer->clip_areas) > 0) {
                ply_pixel_buffer_pop_clip_area (buffer);
        }

        ply_list_free (buffer->clip_areas);
        buffer->clip_areas = NULL;
}

void
ply_pixel_buffer_free (ply_pixel_buffer_t *buffer)
{
        if (buffer == NULL)
                return;

        free_clip_areas (buffer);
        free (buffer->bytes);
        ply_region_free (buffer->updated_areas);
        free (buffer);
}

void
ply_pixel_buffer_get_size (ply_pixel_buffer_t *buffer,
                           ply_rectangle_t    *size)
{
        assert (buffer != NULL);
        assert (size != NULL);

        *size = buffer->area;
}

unsigned long
ply_pixel_buffer_get_width (ply_pixel_buffer_t *buffer)
{
        assert (buffer != NULL);
        return buffer->area.width;
}

unsigned long
ply_pixel_buffer_get_height (ply_pixel_buffer_t *buffer)
{
        assert (buffer != NULL);
        return buffer->area.height;
}

bool
ply_pixel_buffer_is_opaque (ply_pixel_buffer_t *buffer)
{
        assert (buffer != NULL);
        return buffer->is_opaque;
}

void
ply_pixel_buffer_set_opaque (ply_pixel_buffer_t *buffer,
                             bool                is_opaque)
{
        assert (buffer != NULL);
        buffer->is_opaque = is_opaque;
}

ply_region_t *
ply_pixel_buffer_get_updated_areas (ply_pixel_buffer_t *buffer)
{
        return buffer->updated_areas;
}

void
ply_pixel_buffer_fill_with_gradient (ply_pixel_buffer_t *buffer,
                                     ply_rectangle_t    *fill_area,
                                     uint32_t            start,
                                     uint32_t            end)
{
/* The gradient produced is a linear interpolation of the two passed
 * in color stops: start and end.
 *
 * In order to prevent banding when the color stops are too close
 * together, or are stretched over too large an area, we slightly
 * perturb the intermediate colors as we generate them.
 *
 * Before we do this, we store the interpolated color values in a
 * fixed point number with lots of fractional bits.  This is so
 * we don't add noise after the values have been clamped to 8-bits
 *
 * We add random noise to all of the fractional bits of each color
 * channel and also NOISE_BITS worth of noise to the non-fractional
 * part of the color. By default NOISE_BITS is 1.
 *
 * We incorporate the noise by filling the bottom 24 bits of an
 * integer with random bits and then shifting the color channels
 * to the left such that the top 8 bits of the channel overlap
 * the noise by NOISE_BITS. E.g., if NOISE_BITS is 1, then the top
 * 7 bits of each channel won't overlap with the noise, and the 8th
 * bit + fractional bits will.  When the noise and color channel
 * are properly aligned, we add them together, drop the precision
 * of the resulting channels back to 8 bits and stuff the results
 * into a pixel in the pixel buffer.
 */
#define NOISE_BITS 1
/* In the color stops, red is 8 bits starting at position 24
 * (since they're argb32 pixels).
 * We want to move those 8 bits such that the bottom NOISE_BITS
 * of them overlap the top of the 24 bits of generated noise.
 * Of course, green and blue are 8 bits away from red and each
 * other, respectively.
 */
#define RED_SHIFT (32 - (24 + NOISE_BITS))
#define GREEN_SHIFT (RED_SHIFT + 8)
#define BLUE_SHIFT (GREEN_SHIFT + 8)
#define NOISE_MASK (0x00ffffff)

/* Once, we've lined up the color channel we're interested in with
 * the noise, we need to mask out the other channels.
 */
#define COLOR_MASK (0xff << (24 - NOISE_BITS))

        uint32_t red, green, blue, red_step, green_step, blue_step, t, pixel;
        uint32_t x, y;
        /* we use a fixed seed so that the dithering doesn't change on repaints
         * of the same area.
         */
        uint32_t noise = 0x100001;
        ply_rectangle_t cropped_area;

        if (fill_area == NULL)
                fill_area = &buffer->area;

        ply_pixel_buffer_crop_area_to_clip_area (buffer, fill_area, &cropped_area);

        red = (start << RED_SHIFT) & COLOR_MASK;
        green = (start << GREEN_SHIFT) & COLOR_MASK;
        blue = (start << BLUE_SHIFT) & COLOR_MASK;

        t = (end << RED_SHIFT) & COLOR_MASK;
        red_step = (int32_t) (t - red) / (int32_t) buffer->area.height;
        t = (end << GREEN_SHIFT) & COLOR_MASK;
        green_step = (int32_t) (t - green) / (int32_t) buffer->area.height;
        t = (end << BLUE_SHIFT) & COLOR_MASK;
        blue_step = (int32_t) (t - blue) / (int32_t) buffer->area.height;


#define RANDOMIZE(num) (num = (num + (num << 1)) & NOISE_MASK)
#define UNROLLED_PIXEL_COUNT 8

        for (y = buffer->area.y; y < buffer->area.y + buffer->area.height; y++) {
                if (cropped_area.y <= y && y < cropped_area.y + cropped_area.height) {
                        if (cropped_area.width < UNROLLED_PIXEL_COUNT) {
                                for (x = cropped_area.x; x < cropped_area.x + cropped_area.width; x++) {
                                        pixel = 0xff000000;
                                        RANDOMIZE (noise);
                                        pixel |= (((red + noise) & COLOR_MASK) >> RED_SHIFT);
                                        RANDOMIZE (noise);
                                        pixel |= (((green + noise) & COLOR_MASK) >> GREEN_SHIFT);
                                        RANDOMIZE (noise);
                                        pixel |= (((blue + noise) & COLOR_MASK) >> BLUE_SHIFT);

                                        buffer->bytes[y * buffer->area.width + x] = pixel;
                                }
                        } else {
                                uint32_t shaded_set[UNROLLED_PIXEL_COUNT];
                                uint32_t *ptr = &buffer->bytes[y * buffer->area.width + cropped_area.x];
                                for (x = 0; x < UNROLLED_PIXEL_COUNT; x++) {
                                        shaded_set[x] = 0xff000000;
                                        RANDOMIZE (noise);
                                        shaded_set[x] |= (((red + noise) & COLOR_MASK) >> RED_SHIFT);
                                        RANDOMIZE (noise);
                                        shaded_set[x] |= (((green + noise) & COLOR_MASK) >> GREEN_SHIFT);
                                        RANDOMIZE (noise);
                                        shaded_set[x] |= (((blue + noise) & COLOR_MASK) >> BLUE_SHIFT);
                                }
                                for (x = cropped_area.width; x >= UNROLLED_PIXEL_COUNT; x -= UNROLLED_PIXEL_COUNT) {
                                        memcpy (ptr, (void *) shaded_set, UNROLLED_PIXEL_COUNT * sizeof(uint32_t));
                                        ptr += UNROLLED_PIXEL_COUNT;
                                }

                                memcpy (ptr, (void *) shaded_set, x * sizeof(uint32_t));
                        }
                }

                red += red_step;
                green += green_step;
                blue += blue_step;
        }

        ply_region_add_rectangle (buffer->updated_areas, &cropped_area);
}

void
ply_pixel_buffer_fill_with_color (ply_pixel_buffer_t *buffer,
                                  ply_rectangle_t    *fill_area,
                                  double              red,
                                  double              green,
                                  double              blue,
                                  double              alpha)
{
        uint32_t pixel_value;
        ply_rectangle_t cropped_area;

        assert (buffer != NULL);

        if (fill_area == NULL)
                fill_area = &buffer->area;

        ply_pixel_buffer_crop_area_to_clip_area (buffer, fill_area, &cropped_area);

        red *= alpha;
        green *= alpha;
        blue *= alpha;

        pixel_value = PLY_PIXEL_BUFFER_COLOR_TO_PIXEL_VALUE (red, green, blue, alpha);

        ply_pixel_buffer_fill_area_with_pixel_value (buffer, &cropped_area, pixel_value);

        ply_region_add_rectangle (buffer->updated_areas, &cropped_area);
}

void
ply_pixel_buffer_fill_with_hex_color_at_opacity (ply_pixel_buffer_t *buffer,
                                                 ply_rectangle_t    *fill_area,
                                                 uint32_t            hex_color,
                                                 double              opacity)
{
        ply_rectangle_t cropped_area;
        uint32_t pixel_value;
        double red;
        double green;
        double blue;
        double alpha;

        assert (buffer != NULL);

        if (fill_area == NULL)
                fill_area = &buffer->area;

        ply_pixel_buffer_crop_area_to_clip_area (buffer, fill_area, &cropped_area);

        /* if they only gave an rgb hex number, assume an alpha of 0xff
         */
        if ((hex_color & 0xff000000) == 0)
                hex_color = (hex_color << 8) | 0xff;

        red = ((double) (hex_color & 0xff000000) / 0xff000000);
        green = ((double) (hex_color & 0x00ff0000) / 0x00ff0000);
        blue = ((double) (hex_color & 0x0000ff00) / 0x0000ff00);
        alpha = ((double) (hex_color & 0x000000ff) / 0x000000ff);

        alpha *= opacity;

        red *= alpha;
        green *= alpha;
        blue *= alpha;

        pixel_value = PLY_PIXEL_BUFFER_COLOR_TO_PIXEL_VALUE (red, green, blue, alpha);

        ply_pixel_buffer_fill_area_with_pixel_value (buffer, &cropped_area, pixel_value);

        ply_region_add_rectangle (buffer->updated_areas, &cropped_area);
}

void
ply_pixel_buffer_fill_with_hex_color (ply_pixel_buffer_t *buffer,
                                      ply_rectangle_t    *fill_area,
                                      uint32_t            hex_color)
{
        return ply_pixel_buffer_fill_with_hex_color_at_opacity (buffer, fill_area,
                                                                hex_color, 1.0);
}

void
ply_pixel_buffer_fill_with_argb32_data_at_opacity_with_clip (ply_pixel_buffer_t *buffer,
                                                             ply_rectangle_t    *fill_area,
                                                             ply_rectangle_t    *clip_area,
                                                             uint32_t           *data,
                                                             double              opacity)
{
        unsigned long row, column;
        uint8_t opacity_as_byte;
        ply_rectangle_t cropped_area;
        unsigned long x;
        unsigned long y;

        assert (buffer != NULL);

        if (fill_area == NULL)
                fill_area = &buffer->area;

        ply_pixel_buffer_crop_area_to_clip_area (buffer, fill_area, &cropped_area);

        if (clip_area)
                ply_rectangle_intersect (&cropped_area, clip_area, &cropped_area);

        if (cropped_area.width == 0 || cropped_area.height == 0)
                return;

        x = cropped_area.x - fill_area->x;
        y = cropped_area.y - fill_area->y;
        opacity_as_byte = (uint8_t) (opacity * 255.0);

        for (row = y; row < y + cropped_area.height; row++) {
                for (column = x; column < x + cropped_area.width; column++) {
                        uint32_t pixel_value;

                        pixel_value = data[fill_area->width * row + column];
                        if ((pixel_value >> 24) == 0x00)
                                continue;

                        pixel_value = make_pixel_value_translucent (pixel_value, opacity_as_byte);
                        ply_pixel_buffer_blend_value_at_pixel (buffer,
                                                               cropped_area.x + (column - x),
                                                               cropped_area.y + (row - y),
                                                               pixel_value);
                }
        }

        ply_region_add_rectangle (buffer->updated_areas, &cropped_area);
}

void
ply_pixel_buffer_fill_with_argb32_data_at_opacity (ply_pixel_buffer_t *buffer,
                                                   ply_rectangle_t    *fill_area,
                                                   uint32_t           *data,
                                                   double              opacity)
{
        ply_pixel_buffer_fill_with_argb32_data_at_opacity_with_clip (buffer,
                                                                     fill_area,
                                                                     NULL,
                                                                     data, opacity);
}

void
ply_pixel_buffer_fill_with_argb32_data (ply_pixel_buffer_t *buffer,
                                        ply_rectangle_t    *fill_area,
                                        uint32_t           *data)
{
        ply_pixel_buffer_fill_with_argb32_data_at_opacity_with_clip (buffer,
                                                                     fill_area,
                                                                     NULL,
                                                                     data, 1.0);
}

void
ply_pixel_buffer_fill_with_argb32_data_with_clip (ply_pixel_buffer_t *buffer,
                                                  ply_rectangle_t    *fill_area,
                                                  ply_rectangle_t    *clip_area,
                                                  uint32_t           *data)
{
        ply_pixel_buffer_fill_with_argb32_data_at_opacity_with_clip (buffer,
                                                                     fill_area,
                                                                     clip_area,
                                                                     data, 1.0);
}

static void
ply_pixel_buffer_copy_area (ply_pixel_buffer_t *canvas,
                            ply_pixel_buffer_t *source,
                            int x, int y,
                            ply_rectangle_t *cropped_area)
{
        unsigned long row;

        for (row = y; row < y + cropped_area->height; row++) {
                memcpy (canvas->bytes + (cropped_area->y + row - y) * canvas->area.width + cropped_area->x,
                        source->bytes + (row * source->area.width) + x,
                        cropped_area->width * 4);
        }
}

static void
ply_pixel_buffer_blend_area (ply_pixel_buffer_t *canvas,
                            ply_pixel_buffer_t *source,
                            int x, int y,
                            ply_rectangle_t *cropped_area,
                            double opacity)
{
        unsigned long row, column;
        uint8_t opacity_as_byte = (uint8_t) (opacity * 255.0);

        for (row = y; row < y + cropped_area->height; row++) {
                for (column = x; column < x + cropped_area->width; column++) {
                        uint32_t pixel_value;

                        pixel_value = source->bytes[row * source->area.width + column];

                        pixel_value = make_pixel_value_translucent (pixel_value, opacity_as_byte);

                        if ((pixel_value >> 24) == 0x00)
                                continue;

                        ply_pixel_buffer_blend_value_at_pixel (canvas,
                                                               cropped_area->x + (column - x),
                                                               cropped_area->y + (row - y),
                                                               pixel_value);
                }
        }
}

void
ply_pixel_buffer_fill_with_buffer_at_opacity_with_clip (ply_pixel_buffer_t *canvas,
                                                        ply_pixel_buffer_t *source,
                                                        int                 x_offset,
                                                        int                 y_offset,
                                                        ply_rectangle_t    *clip_area,
                                                        float               opacity)
{
        ply_rectangle_t cropped_area;
        unsigned long x;
        unsigned long y;

        assert (canvas != NULL);
        assert (source != NULL);

        cropped_area.x = x_offset;
        cropped_area.y = y_offset;
        cropped_area.width = source->area.width;
        cropped_area.height = source->area.height;

        ply_pixel_buffer_crop_area_to_clip_area (canvas, &cropped_area, &cropped_area);

        if (clip_area)
                ply_rectangle_intersect (&cropped_area, clip_area, &cropped_area);

        if (cropped_area.width == 0 || cropped_area.height == 0)
                return;

        x = cropped_area.x - x_offset;
        y = cropped_area.y - y_offset;

        if (opacity == 1.0 && ply_pixel_buffer_is_opaque (source))
                ply_pixel_buffer_copy_area (canvas, source, x, y, &cropped_area);
        else
                ply_pixel_buffer_blend_area (canvas, source, x, y, &cropped_area,
                                             opacity);

        ply_region_add_rectangle (canvas->updated_areas, &cropped_area);
}

void
ply_pixel_buffer_fill_with_buffer_at_opacity (ply_pixel_buffer_t *canvas,
                                              ply_pixel_buffer_t *source,
                                              int                 x_offset,
                                              int                 y_offset,
                                              float               opacity)
{
        ply_pixel_buffer_fill_with_buffer_at_opacity_with_clip (canvas,
                                                                source,
                                                                x_offset,
                                                                y_offset,
                                                                NULL,
                                                                opacity);
}

void
ply_pixel_buffer_fill_with_buffer_with_clip (ply_pixel_buffer_t *canvas,
                                             ply_pixel_buffer_t *source,
                                             int                 x_offset,
                                             int                 y_offset,
                                             ply_rectangle_t    *clip_area)
{
        ply_pixel_buffer_fill_with_buffer_at_opacity_with_clip (canvas,
                                                                source,
                                                                x_offset,
                                                                y_offset,
                                                                clip_area,
                                                                1.0);
}

void
ply_pixel_buffer_fill_with_buffer (ply_pixel_buffer_t *canvas,
                                   ply_pixel_buffer_t *source,
                                   int                 x_offset,
                                   int                 y_offset)
{
        ply_pixel_buffer_fill_with_buffer_at_opacity_with_clip (canvas,
                                                                source,
                                                                x_offset,
                                                                y_offset,
                                                                NULL,
                                                                1.0);
}

uint32_t *
ply_pixel_buffer_get_argb32_data (ply_pixel_buffer_t *buffer)
{
        return buffer->bytes;
}

static inline uint32_t
ply_pixel_buffer_interpolate (ply_pixel_buffer_t *buffer,
                              double              x,
                              double              y)
{
        int ix;
        int iy;
        int width;
        int height;

        int i;

        int offset_x;
        int offset_y;
        uint32_t pixels[2][2];
        uint32_t reply = 0;
        uint32_t *bytes;

        width = buffer->area.width;
        height = buffer->area.height;


        bytes = ply_pixel_buffer_get_argb32_data (buffer);

        for (offset_y = 0; offset_y < 2; offset_y++) {
                for (offset_x = 0; offset_x < 2; offset_x++) {
                        ix = x + offset_x;
                        iy = y + offset_y;

                        if (ix < 0 || ix >= width || iy < 0 || iy >= height)
                                pixels[offset_y][offset_x] = 0x00000000;
                        else
                                pixels[offset_y][offset_x] = bytes[ix + iy * width];
                }
        }
        if (!pixels[0][0] && !pixels[0][1] && !pixels[1][0] && !pixels[1][1]) return 0;

        ix = x;
        iy = y;
        x -= ix;
        y -= iy;
        for (i = 0; i < 4; i++) {
                uint32_t value = 0;
                uint32_t mask = 0xFF << (i * 8);
                value += ((pixels[0][0]) & mask) * (1 - x) * (1 - y);
                value += ((pixels[0][1]) & mask) * x * (1 - y);
                value += ((pixels[1][0]) & mask) * (1 - x) * y;
                value += ((pixels[1][1]) & mask) * x * y;
                reply |= value & mask;
        }
        return reply;
}

ply_pixel_buffer_t *
ply_pixel_buffer_resize (ply_pixel_buffer_t *old_buffer,
                         long                width,
                         long                height)
{
        ply_pixel_buffer_t *buffer;
        int x, y;
        double old_x, old_y;
        int old_width, old_height;
        float scale_x, scale_y;
        uint32_t *bytes;

        buffer = ply_pixel_buffer_new (width, height);

        bytes = ply_pixel_buffer_get_argb32_data (buffer);

        old_width = old_buffer->area.width;
        old_height = old_buffer->area.height;

        scale_x = ((double) old_width - 1) / MAX (width - 1, 1);
        scale_y = ((double) old_height - 1) / MAX (height - 1, 1);

        for (y = 0; y < height; y++) {
                old_y = y * scale_y;
                for (x = 0; x < width; x++) {
                        old_x = x * scale_x;
                        bytes[x + y * width] =
                                ply_pixel_buffer_interpolate (old_buffer, old_x, old_y);
                }
        }
        return buffer;
}

ply_pixel_buffer_t *
ply_pixel_buffer_rotate (ply_pixel_buffer_t *old_buffer,
                         long                center_x,
                         long                center_y,
                         double              theta_offset)
{
        ply_pixel_buffer_t *buffer;
        int x, y;
        double old_x, old_y;
        int width;
        int height;
        uint32_t *bytes;

        width = old_buffer->area.width;
        height = old_buffer->area.height;

        buffer = ply_pixel_buffer_new (width, height);

        bytes = ply_pixel_buffer_get_argb32_data (buffer);

        double d = sqrt ((center_x * center_x +
                          center_y * center_y));
        double theta = atan2 (-center_y, -center_x) - theta_offset;
        double start_x = center_x + d * cos (theta);
        double start_y = center_y + d * sin (theta);
        double step_x = cos (-theta_offset);
        double step_y = sin (-theta_offset);

        for (y = 0; y < height; y++) {
                old_y = start_y;
                old_x = start_x;
                start_y += step_x;
                start_x -= step_y;
                for (x = 0; x < width; x++) {
                        if (old_x < 0 || old_x > width || old_y < 0 || old_y > height)
                                bytes[x + y * width] = 0;
                        else
                                bytes[x + y * width] =
                                        ply_pixel_buffer_interpolate (old_buffer, old_x, old_y);
                        old_x += step_x;
                        old_y += step_y;
                }
        }
        return buffer;
}

ply_pixel_buffer_t *
ply_pixel_buffer_tile (ply_pixel_buffer_t *old_buffer,
                       long                width,
                       long                height)
{
        long x, y;
        long old_x, old_y;
        long old_width, old_height;
        uint32_t *bytes, *old_bytes;
        ply_pixel_buffer_t *buffer;

        buffer = ply_pixel_buffer_new (width, height);

        old_bytes = ply_pixel_buffer_get_argb32_data (old_buffer);
        bytes = ply_pixel_buffer_get_argb32_data (buffer);

        old_width = old_buffer->area.width;
        old_height = old_buffer->area.height;

        for (y = 0; y < height; y++) {
                old_y = y % old_height;
                for (x = 0; x < width; x++) {
                        old_x = x % old_width;
                        bytes[x + y * width] = old_bytes[old_x + old_y * old_width];
                }
        }
        return buffer;
}

/* vim: set ts=4 sw=4 et ai ci cino={.5s,^-2,+.5s,t0,g0,e-2,n-2,p2s,(0,=.5s,:.5s */