From 47abb3c7659a4eb1214c358796965f92f98fc901 Mon Sep 17 00:00:00 2001 From: =?utf8?q?S=C3=B8ren=20Sandmann=20Pedersen?= Date: Sun, 3 May 2009 01:08:54 -0400 Subject: [PATCH] Move the radial gradient code form pixman-source.c into pixman-radial-gradient.c --- pixman/pixman-radial-gradient.c | 290 ++++++++++++++++++++++++++++++++++++---- pixman/pixman-source.c | 226 +------------------------------ 2 files changed, 265 insertions(+), 251 deletions(-) diff --git a/pixman/pixman-radial-gradient.c b/pixman/pixman-radial-gradient.c index 19853e3..4a45430 100644 --- a/pixman/pixman-radial-gradient.c +++ b/pixman/pixman-radial-gradient.c @@ -1,41 +1,279 @@ /* + * + * Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc. * Copyright © 2000 SuSE, Inc. + * 2005 Lars Knoll & Zack Rusin, Trolltech * Copyright © 2007 Red Hat, Inc. * + * * 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 SuSE not be used in advertising or - * publicity pertaining to distribution of the software without specific, - * written prior permission. SuSE makes no representations about the - * suitability of this software for any purpose. It is provided "as is" - * without express or implied warranty. + * 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. * - * SuSE DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL SuSE - * 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. + * 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. */ #include #include +#include #include "pixman-private.h" static void -radial_gradient_property_changed (pixman_image_t *image) +radial_gradient_get_scanline_32 (pixman_image_t *image, int x, int y, int width, + uint32_t *buffer, uint32_t *mask, uint32_t maskBits) { - image->common.get_scanline_32 = (scanFetchProc)pixmanFetchGradient; - image->common.get_scanline_64 = (scanFetchProc)_pixman_image_get_scanline_64_generic; + /* + * In the radial gradient problem we are given two circles (c₁,r₁) and + * (c₂,r₂) that define the gradient itself. Then, for any point p, we + * must compute the value(s) of t within [0.0, 1.0] representing the + * circle(s) that would color the point. + * + * There are potentially two values of t since the point p can be + * colored by both sides of the circle, (which happens whenever one + * circle is not entirely contained within the other). + * + * If we solve for a value of t that is outside of [0.0, 1.0] then we + * use the extend mode (NONE, REPEAT, REFLECT, or PAD) to map to a + * value within [0.0, 1.0]. + * + * Here is an illustration of the problem: + * + * p₂ + * p • + * • ╲ + * · ╲r₂ + * p₁ · ╲ + * • θ╲ + * ╲ ╌╌• + * ╲r₁ · c₂ + * θ╲ · + * ╌╌• + * c₁ + * + * Given (c₁,r₁), (c₂,r₂) and p, we must find an angle θ such that two + * points p₁ and p₂ on the two circles are collinear with p. Then, the + * desired value of t is the ratio of the length of p₁p to the length + * of p₁p₂. + * + * So, we have six unknown values: (p₁x, p₁y), (p₂x, p₂y), θ and t. + * We can also write six equations that constrain the problem: + * + * Point p₁ is a distance r₁ from c₁ at an angle of θ: + * + * 1. p₁x = c₁x + r₁·cos θ + * 2. p₁y = c₁y + r₁·sin θ + * + * Point p₂ is a distance r₂ from c₂ at an angle of θ: + * + * 3. p₂x = c₂x + r2·cos θ + * 4. p₂y = c₂y + r2·sin θ + * + * Point p lies at a fraction t along the line segment p₁p₂: + * + * 5. px = t·p₂x + (1-t)·p₁x + * 6. py = t·p₂y + (1-t)·p₁y + * + * To solve, first subtitute 1-4 into 5 and 6: + * + * px = t·(c₂x + r₂·cos θ) + (1-t)·(c₁x + r₁·cos θ) + * py = t·(c₂y + r₂·sin θ) + (1-t)·(c₁y + r₁·sin θ) + * + * Then solve each for cos θ and sin θ expressed as a function of t: + * + * cos θ = (-(c₂x - c₁x)·t + (px - c₁x)) / ((r₂-r₁)·t + r₁) + * sin θ = (-(c₂y - c₁y)·t + (py - c₁y)) / ((r₂-r₁)·t + r₁) + * + * To simplify this a bit, we define new variables for several of the + * common terms as shown below: + * + * p₂ + * p • + * • ╲ + * · ┆ ╲r₂ + * p₁ · ┆ ╲ + * • pdy┆ ╲ + * ╲ ┆ •c₂ + * ╲r₁ ┆ · ┆ + * ╲ ·┆ ┆cdy + * •╌╌╌╌┴╌╌╌╌╌╌╌┘ + * c₁ pdx cdx + * + * cdx = (c₂x - c₁x) + * cdy = (c₂y - c₁y) + * dr = r₂-r₁ + * pdx = px - c₁x + * pdy = py - c₁y + * + * Note that cdx, cdy, and dr do not depend on point p at all, so can + * be pre-computed for the entire gradient. The simplifed equations + * are now: + * + * cos θ = (-cdx·t + pdx) / (dr·t + r₁) + * sin θ = (-cdy·t + pdy) / (dr·t + r₁) + * + * Finally, to get a single function of t and eliminate the last + * unknown θ, we use the identity sin²θ + cos²θ = 1. First, square + * each equation, (we knew a quadratic was coming since it must be + * possible to obtain two solutions in some cases): + * + * cos²θ = (cdx²t² - 2·cdx·pdx·t + pdx²) / (dr²·t² + 2·r₁·dr·t + r₁²) + * sin²θ = (cdy²t² - 2·cdy·pdy·t + pdy²) / (dr²·t² + 2·r₁·dr·t + r₁²) + * + * Then add both together, set the result equal to 1, and express as a + * standard quadratic equation in t of the form At² + Bt + C = 0 + * + * (cdx² + cdy² - dr²)·t² - 2·(cdx·pdx + cdy·pdy + r₁·dr)·t + (pdx² + pdy² - r₁²) = 0 + * + * In other words: + * + * A = cdx² + cdy² - dr² + * B = -2·(pdx·cdx + pdy·cdy + r₁·dr) + * C = pdx² + pdy² - r₁² + * + * And again, notice that A does not depend on p, so can be + * precomputed. From here we just use the quadratic formula to solve + * for t: + * + * t = (-2·B ± ⎷(B² - 4·A·C)) / 2·A + */ + + gradient_t *gradient = (gradient_t *)image; + source_image_t *source = (source_image_t *)image; + radial_gradient_t *radial = (radial_gradient_t *)image; + uint32_t *end = buffer + width; + GradientWalker walker; + pixman_bool_t affine = TRUE; + double cx = 1.; + double cy = 0.; + double cz = 0.; + double rx = x + 0.5; + double ry = y + 0.5; + double rz = 1.; + + _pixman_gradient_walker_init (&walker, gradient, source->common.repeat); + + if (source->common.transform) { + pixman_vector_t v; + /* 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 (!pixman_transform_point_3d (source->common.transform, &v)) + return; + + cx = source->common.transform->matrix[0][0]/65536.; + cy = source->common.transform->matrix[1][0]/65536.; + cz = source->common.transform->matrix[2][0]/65536.; + rx = v.vector[0]/65536.; + ry = v.vector[1]/65536.; + rz = v.vector[2]/65536.; + affine = source->common.transform->matrix[2][0] == 0 && v.vector[2] == pixman_fixed_1; + } + + if (affine) { + while (buffer < end) { + if (!mask || *mask++ & maskBits) + { + double pdx, pdy; + double B, C; + double det; + double c1x = radial->c1.x / 65536.0; + double c1y = radial->c1.y / 65536.0; + double r1 = radial->c1.radius / 65536.0; + pixman_fixed_48_16_t t; + + pdx = rx - c1x; + pdy = ry - c1y; + + B = -2 * ( pdx * radial->cdx + + pdy * radial->cdy + + r1 * radial->dr); + C = (pdx * pdx + pdy * pdy - r1 * r1); + + det = (B * B) - (4 * radial->A * C); + if (det < 0.0) + det = 0.0; + + if (radial->A < 0) + t = (pixman_fixed_48_16_t) ((- B - sqrt(det)) / (2.0 * radial->A) * 65536); + else + t = (pixman_fixed_48_16_t) ((- B + sqrt(det)) / (2.0 * radial->A) * 65536); + + *(buffer) = _pixman_gradient_walker_pixel (&walker, t); + } + ++buffer; + + rx += cx; + ry += cy; + } + } else { + /* projective */ + while (buffer < end) { + if (!mask || *mask++ & maskBits) + { + double pdx, pdy; + double B, C; + double det; + double c1x = radial->c1.x / 65536.0; + double c1y = radial->c1.y / 65536.0; + double r1 = radial->c1.radius / 65536.0; + pixman_fixed_48_16_t t; + double x, y; + + if (rz != 0) { + x = rx/rz; + y = ry/rz; + } else { + x = y = 0.; + } + + pdx = x - c1x; + pdy = y - c1y; + + B = -2 * ( pdx * radial->cdx + + pdy * radial->cdy + + r1 * radial->dr); + C = (pdx * pdx + pdy * pdy - r1 * r1); + + det = (B * B) - (4 * radial->A * C); + if (det < 0.0) + det = 0.0; + + if (radial->A < 0) + t = (pixman_fixed_48_16_t) ((- B - sqrt(det)) / (2.0 * radial->A) * 65536); + else + t = (pixman_fixed_48_16_t) ((- B + sqrt(det)) / (2.0 * radial->A) * 65536); + + *(buffer) = _pixman_gradient_walker_pixel (&walker, t); + } + ++buffer; + + rx += cx; + ry += cy; + rz += cz; + } + } + } static void -radial_gradient_get_scanline_32 (pixman_image_t *image, int x, int y, int width, - uint32_t *buffer, uint32_t *mask, uint32_t maskBits) +radial_gradient_property_changed (pixman_image_t *image) { - + image->common.get_scanline_32 = (scanFetchProc)radial_gradient_get_scanline_32; + image->common.get_scanline_64 = (scanFetchProc)_pixman_image_get_scanline_64_generic; } PIXMAN_EXPORT pixman_image_t * @@ -48,24 +286,24 @@ pixman_image_create_radial_gradient (pixman_point_fixed_t *inner, { pixman_image_t *image; radial_gradient_t *radial; - + return_val_if_fail (n_stops >= 2, NULL); - + image = _pixman_image_allocate(); - + if (!image) return NULL; - + radial = &image->radial; - + if (!_pixman_init_gradient (&radial->common, stops, n_stops)) { free (image); return NULL; } - + image->type = RADIAL; - + radial->c1.x = inner->x; radial->c1.y = inner->y; radial->c1.radius = inner_radius; @@ -78,9 +316,9 @@ pixman_image_create_radial_gradient (pixman_point_fixed_t *inner, radial->A = (radial->cdx * radial->cdx + radial->cdy * radial->cdy - radial->dr * radial->dr); - + image->common.property_changed = radial_gradient_property_changed; - + radial_gradient_property_changed (image); return image; diff --git a/pixman/pixman-source.c b/pixman/pixman-source.c index d3dce87..dfdb183 100644 --- a/pixman/pixman-source.c +++ b/pixman/pixman-source.c @@ -47,232 +47,8 @@ pixmanFetchGradient(gradient_t *gradient, int x, int y, int width, if (pict->common.type == LINEAR) { assert (0); } else { -/* - * In the radial gradient problem we are given two circles (c₁,r₁) and - * (c₂,r₂) that define the gradient itself. Then, for any point p, we - * must compute the value(s) of t within [0.0, 1.0] representing the - * circle(s) that would color the point. - * - * There are potentially two values of t since the point p can be - * colored by both sides of the circle, (which happens whenever one - * circle is not entirely contained within the other). - * - * If we solve for a value of t that is outside of [0.0, 1.0] then we - * use the extend mode (NONE, REPEAT, REFLECT, or PAD) to map to a - * value within [0.0, 1.0]. - * - * Here is an illustration of the problem: - * - * p₂ - * p • - * • ╲ - * · ╲r₂ - * p₁ · ╲ - * • θ╲ - * ╲ ╌╌• - * ╲r₁ · c₂ - * θ╲ · - * ╌╌• - * c₁ - * - * Given (c₁,r₁), (c₂,r₂) and p, we must find an angle θ such that two - * points p₁ and p₂ on the two circles are collinear with p. Then, the - * desired value of t is the ratio of the length of p₁p to the length - * of p₁p₂. - * - * So, we have six unknown values: (p₁x, p₁y), (p₂x, p₂y), θ and t. - * We can also write six equations that constrain the problem: - * - * Point p₁ is a distance r₁ from c₁ at an angle of θ: - * - * 1. p₁x = c₁x + r₁·cos θ - * 2. p₁y = c₁y + r₁·sin θ - * - * Point p₂ is a distance r₂ from c₂ at an angle of θ: - * - * 3. p₂x = c₂x + r2·cos θ - * 4. p₂y = c₂y + r2·sin θ - * - * Point p lies at a fraction t along the line segment p₁p₂: - * - * 5. px = t·p₂x + (1-t)·p₁x - * 6. py = t·p₂y + (1-t)·p₁y - * - * To solve, first subtitute 1-4 into 5 and 6: - * - * px = t·(c₂x + r₂·cos θ) + (1-t)·(c₁x + r₁·cos θ) - * py = t·(c₂y + r₂·sin θ) + (1-t)·(c₁y + r₁·sin θ) - * - * Then solve each for cos θ and sin θ expressed as a function of t: - * - * cos θ = (-(c₂x - c₁x)·t + (px - c₁x)) / ((r₂-r₁)·t + r₁) - * sin θ = (-(c₂y - c₁y)·t + (py - c₁y)) / ((r₂-r₁)·t + r₁) - * - * To simplify this a bit, we define new variables for several of the - * common terms as shown below: - * - * p₂ - * p • - * • ╲ - * · ┆ ╲r₂ - * p₁ · ┆ ╲ - * • pdy┆ ╲ - * ╲ ┆ •c₂ - * ╲r₁ ┆ · ┆ - * ╲ ·┆ ┆cdy - * •╌╌╌╌┴╌╌╌╌╌╌╌┘ - * c₁ pdx cdx - * - * cdx = (c₂x - c₁x) - * cdy = (c₂y - c₁y) - * dr = r₂-r₁ - * pdx = px - c₁x - * pdy = py - c₁y - * - * Note that cdx, cdy, and dr do not depend on point p at all, so can - * be pre-computed for the entire gradient. The simplifed equations - * are now: - * - * cos θ = (-cdx·t + pdx) / (dr·t + r₁) - * sin θ = (-cdy·t + pdy) / (dr·t + r₁) - * - * Finally, to get a single function of t and eliminate the last - * unknown θ, we use the identity sin²θ + cos²θ = 1. First, square - * each equation, (we knew a quadratic was coming since it must be - * possible to obtain two solutions in some cases): - * - * cos²θ = (cdx²t² - 2·cdx·pdx·t + pdx²) / (dr²·t² + 2·r₁·dr·t + r₁²) - * sin²θ = (cdy²t² - 2·cdy·pdy·t + pdy²) / (dr²·t² + 2·r₁·dr·t + r₁²) - * - * Then add both together, set the result equal to 1, and express as a - * standard quadratic equation in t of the form At² + Bt + C = 0 - * - * (cdx² + cdy² - dr²)·t² - 2·(cdx·pdx + cdy·pdy + r₁·dr)·t + (pdx² + pdy² - r₁²) = 0 - * - * In other words: - * - * A = cdx² + cdy² - dr² - * B = -2·(pdx·cdx + pdy·cdy + r₁·dr) - * C = pdx² + pdy² - r₁² - * - * And again, notice that A does not depend on p, so can be - * precomputed. From here we just use the quadratic formula to solve - * for t: - * - * t = (-2·B ± ⎷(B² - 4·A·C)) / 2·A - */ if (pict->common.type == RADIAL) { - /* radial or conical */ - pixman_bool_t affine = TRUE; - double cx = 1.; - double cy = 0.; - double cz = 0.; - double rx = x + 0.5; - double ry = y + 0.5; - double rz = 1.; - - if (pict->common.transform) { - pixman_vector_t v; - /* 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 (!pixman_transform_point_3d (pict->common.transform, &v)) - return; - - cx = pict->common.transform->matrix[0][0]/65536.; - cy = pict->common.transform->matrix[1][0]/65536.; - cz = pict->common.transform->matrix[2][0]/65536.; - rx = v.vector[0]/65536.; - ry = v.vector[1]/65536.; - rz = v.vector[2]/65536.; - affine = pict->common.transform->matrix[2][0] == 0 && v.vector[2] == pixman_fixed_1; - } - - radial_gradient_t *radial = (radial_gradient_t *)pict; - if (affine) { - while (buffer < end) { - if (!mask || *mask++ & maskBits) - { - double pdx, pdy; - double B, C; - double det; - double c1x = radial->c1.x / 65536.0; - double c1y = radial->c1.y / 65536.0; - double r1 = radial->c1.radius / 65536.0; - pixman_fixed_48_16_t t; - - pdx = rx - c1x; - pdy = ry - c1y; - - B = -2 * ( pdx * radial->cdx - + pdy * radial->cdy - + r1 * radial->dr); - C = (pdx * pdx + pdy * pdy - r1 * r1); - - det = (B * B) - (4 * radial->A * C); - if (det < 0.0) - det = 0.0; - - if (radial->A < 0) - t = (pixman_fixed_48_16_t) ((- B - sqrt(det)) / (2.0 * radial->A) * 65536); - else - t = (pixman_fixed_48_16_t) ((- B + sqrt(det)) / (2.0 * radial->A) * 65536); - - *(buffer) = _pixman_gradient_walker_pixel (&walker, t); - } - ++buffer; - - rx += cx; - ry += cy; - } - } else { - /* projective */ - while (buffer < end) { - if (!mask || *mask++ & maskBits) - { - double pdx, pdy; - double B, C; - double det; - double c1x = radial->c1.x / 65536.0; - double c1y = radial->c1.y / 65536.0; - double r1 = radial->c1.radius / 65536.0; - pixman_fixed_48_16_t t; - double x, y; - - if (rz != 0) { - x = rx/rz; - y = ry/rz; - } else { - x = y = 0.; - } - - pdx = x - c1x; - pdy = y - c1y; - - B = -2 * ( pdx * radial->cdx - + pdy * radial->cdy - + r1 * radial->dr); - C = (pdx * pdx + pdy * pdy - r1 * r1); - - det = (B * B) - (4 * radial->A * C); - if (det < 0.0) - det = 0.0; - - if (radial->A < 0) - t = (pixman_fixed_48_16_t) ((- B - sqrt(det)) / (2.0 * radial->A) * 65536); - else - t = (pixman_fixed_48_16_t) ((- B + sqrt(det)) / (2.0 * radial->A) * 65536); - - *(buffer) = _pixman_gradient_walker_pixel (&walker, t); - } - ++buffer; - - rx += cx; - ry += cy; - rz += cz; - } - } + assert (0); } else /* SourcePictTypeConical */ { /* radial or conical */ pixman_bool_t affine = TRUE; -- 2.7.4