The Tor Browser: gfx/cairo/libpixman/src/pixman-linear-gradient.c@6474c204b198 (annotated)

gfx/cairo/libpixman/src/pixman-linear-gradient.c@6474c204b198 (annotated)

gfx/cairo/libpixman/src/pixman-linear-gradient.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: c; c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t; -*- */
 /*
  * Copyright © 2000 SuSE, Inc.
  * Copyright © 2007 Red Hat, Inc.
  * Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc.
  *             2005 Lars Knoll & Zack Rusin, Trolltech
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
  * the above copyright notice appear in all copies and that both that
  * copyright notice and this permission notice appear in supporting
  * documentation, and that the name of Keith Packard not be used in
  * advertising or publicity pertaining to distribution of the software without
  * specific, written prior permission.  Keith Packard makes no
  * representations about the suitability of this software for any purpose.  It
  * is provided "as is" without express or implied warranty.
  *
  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  * SOFTWARE.
  */
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
 #include <stdlib.h>
 #include "pixman-private.h"
 #include "pixman-dither.h"
 static pixman_bool_t
 linear_gradient_is_horizontal (pixman_image_t *image,
 			       int             x,
 			       int             y,
 			       int             width,
 			       int             height)
 {
     linear_gradient_t *linear = (linear_gradient_t *)image;
     pixman_vector_t v;
     pixman_fixed_32_32_t l;
     pixman_fixed_48_16_t dx, dy;
     double inc;
     if (image->common.transform)
     {
 	/* projective transformation */
 	if (image->common.transform->matrix[2][0] != 0 ||
 	    image->common.transform->matrix[2][1] != 0 ||
 	    image->common.transform->matrix[2][2] == 0)
 	{
 	    return FALSE;
 	}
 	v.vector[0] = image->common.transform->matrix[0][1];
 	v.vector[1] = image->common.transform->matrix[1][1];
 	v.vector[2] = image->common.transform->matrix[2][2];
     }
     else
     {
 	v.vector[0] = 0;
 	v.vector[1] = pixman_fixed_1;
 	v.vector[2] = pixman_fixed_1;
     }
     dx = linear->p2.x - linear->p1.x;
     dy = linear->p2.y - linear->p1.y;
     l = dx * dx + dy * dy;
     if (l == 0)
 	return FALSE;
     /*
      * compute how much the input of the gradient walked changes
      * when moving vertically through the whole image
      */
     inc = height * (double) pixman_fixed_1 * pixman_fixed_1 *
 	(dx * v.vector[0] + dy * v.vector[1]) /
 	(v.vector[2] * (double) l);
     /* check that casting to integer would result in 0 */
     if (-1 < inc && inc < 1)
 	return TRUE;
     return FALSE;
 }
 static uint32_t *
 linear_get_scanline_narrow (pixman_iter_t  *iter,
 			    const uint32_t *mask)
 {
     pixman_image_t *image  = iter->image;
     int             x      = iter->x;
     int             y      = iter->y;
     int             width  = iter->width;
     uint32_t *      buffer = iter->buffer;
     pixman_vector_t v, unit;
     pixman_fixed_32_32_t l;
     pixman_fixed_48_16_t dx, dy;
     gradient_t *gradient = (gradient_t *)image;
     linear_gradient_t *linear = (linear_gradient_t *)image;
     uint32_t *end = buffer + width;
     pixman_gradient_walker_t walker;
     _pixman_gradient_walker_init (&walker, gradient, image->common.repeat);
     /* reference point is the center of the pixel */
     v.vector[0] = pixman_int_to_fixed (x) + pixman_fixed_1 / 2;
     v.vector[1] = pixman_int_to_fixed (y) + pixman_fixed_1 / 2;
     v.vector[2] = pixman_fixed_1;
     if (image->common.transform)
     {
 	if (!pixman_transform_point_3d (image->common.transform, &v))
 	    return iter->buffer;
 	unit.vector[0] = image->common.transform->matrix[0][0];
 	unit.vector[1] = image->common.transform->matrix[1][0];
 	unit.vector[2] = image->common.transform->matrix[2][0];
     }
     else
     {
 	unit.vector[0] = pixman_fixed_1;
 	unit.vector[1] = 0;
 	unit.vector[2] = 0;
     }
     dx = linear->p2.x - linear->p1.x;
     dy = linear->p2.y - linear->p1.y;
     l = dx * dx + dy * dy;
     if (l == 0 || unit.vector[2] == 0)
     {
 	/* affine transformation only */
         pixman_fixed_32_32_t t, next_inc;
 	double inc;
 	if (l == 0 || v.vector[2] == 0)
 	{
 	    t = 0;
 	    inc = 0;
 	}
 	else
 	{
 	    double invden, v2;
 	    invden = pixman_fixed_1 * (double) pixman_fixed_1 /
 		(l * (double) v.vector[2]);
 	    v2 = v.vector[2] * (1. / pixman_fixed_1);
 	    t = ((dx * v.vector[0] + dy * v.vector[1]) -
 		 (dx * linear->p1.x + dy * linear->p1.y) * v2) * invden;
 	    inc = (dx * unit.vector[0] + dy * unit.vector[1]) * invden;
 	}
 	next_inc = 0;
 	if (((pixman_fixed_32_32_t )(inc * width)) == 0)
 	{
 	    register uint32_t color;
 	    color = _pixman_gradient_walker_pixel (&walker, t);
 	    while (buffer < end)
 		*buffer++ = color;
 	}
 	else
 	{
 	    int i;
 	    i = 0;
 	    while (buffer < end)
 	    {
 		if (!mask || *mask++)
 		{
 		    *buffer = _pixman_gradient_walker_pixel (&walker,
 							     t + next_inc);
 		}
 		i++;
 		next_inc = inc * i;
 		buffer++;
 	    }
 	}
     }
     else
     {
 	/* projective transformation */
         double t;
 	t = 0;
 	while (buffer < end)
 	{
 	    if (!mask || *mask++)
 	    {
 	        if (v.vector[2] != 0)
 		{
 		    double invden, v2;
 		    invden = pixman_fixed_1 * (double) pixman_fixed_1 /
 			(l * (double) v.vector[2]);
 		    v2 = v.vector[2] * (1. / pixman_fixed_1);
 		    t = ((dx * v.vector[0] + dy * v.vector[1]) -
 			 (dx * linear->p1.x + dy * linear->p1.y) * v2) * invden;
 		}
 		*buffer = _pixman_gradient_walker_pixel (&walker, t);
 	    }
 	    ++buffer;
 	    v.vector[0] += unit.vector[0];
 	    v.vector[1] += unit.vector[1];
 	    v.vector[2] += unit.vector[2];
 	}
     }
     iter->y++;
     return iter->buffer;
 }
 static uint32_t *
 linear_get_scanline_16 (pixman_iter_t  *iter,
 			const uint32_t *mask)
 {
     pixman_image_t *image  = iter->image;
     int             x      = iter->x;
     int             y      = iter->y;
     int             width  = iter->width;
     uint16_t *      buffer = (uint16_t*)iter->buffer;
     pixman_bool_t   toggle = ((x ^ y) & 1);
     pixman_vector_t v, unit;
     pixman_fixed_32_32_t l;
     pixman_fixed_48_16_t dx, dy;
     gradient_t *gradient = (gradient_t *)image;
     linear_gradient_t *linear = (linear_gradient_t *)image;
     uint16_t *end = buffer + width;
     pixman_gradient_walker_t walker;
     _pixman_gradient_walker_init (&walker, gradient, image->common.repeat);
     /* reference point is the center of the pixel */
     v.vector[0] = pixman_int_to_fixed (x) + pixman_fixed_1 / 2;
     v.vector[1] = pixman_int_to_fixed (y) + pixman_fixed_1 / 2;
     v.vector[2] = pixman_fixed_1;
     if (image->common.transform)
     {
 	if (!pixman_transform_point_3d (image->common.transform, &v))
 	    return iter->buffer;
 	unit.vector[0] = image->common.transform->matrix[0][0];
 	unit.vector[1] = image->common.transform->matrix[1][0];
 	unit.vector[2] = image->common.transform->matrix[2][0];
     }
     else
     {
 	unit.vector[0] = pixman_fixed_1;
 	unit.vector[1] = 0;
 	unit.vector[2] = 0;
     }
     dx = linear->p2.x - linear->p1.x;
     dy = linear->p2.y - linear->p1.y;
     l = dx * dx + dy * dy;
     if (l == 0 || unit.vector[2] == 0)
     {
 	/* affine transformation only */
         pixman_fixed_32_32_t t, next_inc;
 	double inc;
 	if (l == 0 || v.vector[2] == 0)
 	{
 	    t = 0;
 	    inc = 0;
 	}
 	else
 	{
 	    double invden, v2;
 	    invden = pixman_fixed_1 * (double) pixman_fixed_1 /
 		(l * (double) v.vector[2]);
 	    v2 = v.vector[2] * (1. / pixman_fixed_1);
 	    t = ((dx * v.vector[0] + dy * v.vector[1]) -
 		 (dx * linear->p1.x + dy * linear->p1.y) * v2) * invden;
 	    inc = (dx * unit.vector[0] + dy * unit.vector[1]) * invden;
 	}
 	next_inc = 0;
 	if (((pixman_fixed_32_32_t )(inc * width)) == 0)
 	{
 	    register uint32_t color;
 	    uint16_t dither_diff;
 	    uint16_t color16;
 	    uint16_t color16b;
 	    color = _pixman_gradient_walker_pixel (&walker, t);
 	    color16 = dither_8888_to_0565(color, toggle);
 	    color16b = dither_8888_to_0565(color, toggle^1);
 	    // compute the difference
 	    dither_diff =  color16 ^ color16b;
 	    while (buffer < end) {
 		*buffer++ = color16;
 		// use dither_diff to toggle between color16 and color16b
 		color16 ^= dither_diff;
 		toggle ^= 1;
 	    }
 	}
 	else
 	{
 	    int i;
 	    i = 0;
 	    while (buffer < end)
 	    {
 		if (!mask || *mask++)
 		{
 		    *buffer = dither_8888_to_0565(_pixman_gradient_walker_pixel (&walker,
 										 t + next_inc),
 						  toggle);
 		}
 		toggle ^= 1;
 		i++;
 		next_inc = inc * i;
 		buffer++;
 	    }
 	}
     }
     else
     {
 	/* projective transformation */
         double t;
 	t = 0;
 	while (buffer < end)
 	{
 	    if (!mask || *mask++)
 	    {
 	        if (v.vector[2] != 0)
 		{
 		    double invden, v2;
 		    invden = pixman_fixed_1 * (double) pixman_fixed_1 /
 			(l * (double) v.vector[2]);
 		    v2 = v.vector[2] * (1. / pixman_fixed_1);
 		    t = ((dx * v.vector[0] + dy * v.vector[1]) -
 			 (dx * linear->p1.x + dy * linear->p1.y) * v2) * invden;
 		}
 		*buffer = dither_8888_to_0565(_pixman_gradient_walker_pixel (&walker, t),
 					      toggle);
 	    }
 	    toggle ^= 1;
 	    ++buffer;
 	    v.vector[0] += unit.vector[0];
 	    v.vector[1] += unit.vector[1];
 	    v.vector[2] += unit.vector[2];
 	}
     }
     iter->y++;
     return iter->buffer;
 }
 static uint32_t *
 linear_get_scanline_wide (pixman_iter_t *iter, const uint32_t *mask)
 {
     uint32_t *buffer = linear_get_scanline_narrow (iter, NULL);
     pixman_expand_to_float (
 	(argb_t *)buffer, buffer, PIXMAN_a8r8g8b8, iter->width);
     return buffer;
 }
 void
 _pixman_linear_gradient_iter_init (pixman_image_t *image, pixman_iter_t  *iter)
 {
     // XXX: we can't use this optimization when dithering
     if (0 && linear_gradient_is_horizontal (
 	    iter->image, iter->x, iter->y, iter->width, iter->height))
     {
 	if (iter->iter_flags & ITER_16)
 	    linear_get_scanline_16 (iter, NULL);
 	else if (iter->iter_flags & ITER_NARROW)
 	    linear_get_scanline_narrow (iter, NULL);
 	else
 	    linear_get_scanline_wide (iter, NULL);
 	iter->get_scanline = _pixman_iter_get_scanline_noop;
     }
     else
     {
 	if (iter->iter_flags & ITER_16)
 	    iter->get_scanline = linear_get_scanline_16;
 	else if (iter->iter_flags & ITER_NARROW)
 	    iter->get_scanline = linear_get_scanline_narrow;
 	else
 	    iter->get_scanline = linear_get_scanline_wide;
     }
 }
 PIXMAN_EXPORT pixman_image_t *
 pixman_image_create_linear_gradient (const pixman_point_fixed_t *  p1,
                                      const pixman_point_fixed_t *  p2,
                                      const pixman_gradient_stop_t *stops,
                                      int                           n_stops)
 {
     pixman_image_t *image;
     linear_gradient_t *linear;
     image = _pixman_image_allocate ();
     if (!image)
 	return NULL;
     linear = &image->linear;
     if (!_pixman_init_gradient (&linear->common, stops, n_stops))
     {
 	free (image);
 	return NULL;
     }
     linear->p1 = *p1;
     linear->p2 = *p2;
     image->type = LINEAR;
     return image;
 }

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gfx/cairo/libpixman/src/pixman-linear-gradient.c@6474c204b198 (annotated)

gfx/cairo/libpixman/src/pixman-linear-gradient.c