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/* This file is part of the KDE project.
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* art_render_misc.c: Here I store some routines I feel should be in libart :)
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* Copyright (C) 2002, The Karbon Developers
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* This code is adapted from :
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* art_render_gradient.c: Gradient image source for modular rendering.
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* Libart_LGPL - library of basic graphic primitives
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* Copyright (C) 2000 Raph Levien
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* Authors: Raph Levien <raph@acm.org>
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* Alexander Larsson <alla@lysator.liu.se>
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#include "art_render_misc.h"
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typedef struct _ArtImageSourceGradLin ArtImageSourceGradLin;
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typedef struct _ArtImageSourceGradRad ArtImageSourceGradRad;
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typedef struct _ArtImageSourceGradCon ArtImageSourceGradCon;
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struct _ArtImageSourceGradLin {
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const ArtGradientLinear *gradient;
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struct _ArtImageSourceGradRad {
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const ArtGradientRadial *gradient;
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struct _ArtImageSourceGradCon {
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const ArtGradientConical *gradient;
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* art_karbon_render_gradient_setpix: Set a gradient pixel.
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* @render: The render object.
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* @dst: Pointer to destination (where to store pixel).
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* @n_stops: Number of stops in @stops.
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* @stops: The stops for the gradient.
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* @offset: The offset.
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* @n_stops must be > 0.
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* Sets a gradient pixel, storing it at @dst.
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art_karbon_render_gradient_setpix (ArtRender *render,
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int n_stops, ArtGradientStop *stops,
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int n_ch = render->n_chan + 1;
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for (ix = 0; ix < n_stops; ix++)
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if (stops[ix].offset > offset)
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/* stops[ix - 1].offset < offset < stops[ix].offset */
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if (ix > 0 && ix < n_stops)
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off0 = stops[ix - 1].offset;
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off1 = stops[ix].offset;
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if (fabs (off1 - off0) > EPSILON)
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interp = (offset - off0) / (off1 - off0);
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for (j = 0; j < n_ch; j++)
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z0 = stops[ix - 1].color[j];
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z1 = stops[ix].color[j];
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z = floor (z0 + (z1 - z0) * interp + 0.5);
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if (render->buf_depth == 8)
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dst[j] = ART_PIX_8_FROM_MAX (z);
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else /* (render->buf_depth == 16) */
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((art_u16 *)dst)[j] = z;
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else if (ix == n_stops)
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for (j = 0; j < n_ch; j++)
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z = stops[ix].color[j];
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if (render->buf_depth == 8)
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dst[j] = ART_PIX_8_FROM_MAX (z);
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else /* (render->buf_depth == 16) */
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((art_u16 *)dst)[j] = z;
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art_karbon_render_gradient_linear_done (ArtRenderCallback *self, ArtRender *render)
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art_karbon_render_gradient_linear_render (ArtRenderCallback *self, ArtRender *render,
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ArtImageSourceGradLin *z = (ArtImageSourceGradLin *)self;
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const ArtGradientLinear *gradient = z->gradient;
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int pixstride = (render->n_chan + 1) * (render->depth >> 3);
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int width = render->x1 - render->x0;
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double offset, d_offset;
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double actual_offset;
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int n_stops = gradient->n_stops;
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ArtGradientStop *stops = gradient->stops;
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art_u8 *bufp = render->image_buf;
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ArtGradientSpread spread = gradient->spread;
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offset = render->x0 * gradient->a + y * gradient->b + gradient->c;
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d_offset = gradient->a;
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for (x = 0; x < width; x++)
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if (spread == ART_GRADIENT_PAD)
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actual_offset = offset;
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else if (spread == ART_GRADIENT_REPEAT)
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actual_offset = offset - floor (offset);
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else /* (spread == ART_GRADIENT_REFLECT) */
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tmp = offset - 2 * floor (0.5 * offset);
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actual_offset = tmp > 1 ? 2 - tmp : tmp;
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art_karbon_render_gradient_setpix (render, bufp, n_stops, stops, actual_offset);
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art_karbon_render_gradient_linear_negotiate (ArtImageSource *self, ArtRender *render,
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ArtImageSourceFlags *p_flags,
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int *p_buf_depth, ArtAlphaType *p_alpha)
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self->super.render = art_karbon_render_gradient_linear_render;
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*p_buf_depth = render->depth;
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*p_alpha = ART_ALPHA_PREMUL;
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* art_karbon_render_gradient_linear: Add a linear gradient image source.
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* @render: The render object.
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* @gradient: The linear gradient.
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* Adds the linear gradient @gradient as the image source for rendering
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* in the render object @render.
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art_karbon_render_gradient_linear (ArtRender *render,
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const ArtGradientLinear *gradient,
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ArtFilterLevel level)
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ArtImageSourceGradLin *image_source = art_new (ArtImageSourceGradLin, 1);
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image_source->super.super.render = NULL;
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image_source->super.super.done = art_karbon_render_gradient_linear_done;
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image_source->super.negotiate = art_karbon_render_gradient_linear_negotiate;
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image_source->gradient = gradient;
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art_render_add_image_source (render, &image_source->super);
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art_karbon_render_gradient_radial_done (ArtRenderCallback *self, ArtRender *render)
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art_karbon_render_gradient_radial_render (ArtRenderCallback *self, ArtRender *render,
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ArtImageSourceGradRad *z = (ArtImageSourceGradRad *)self;
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const ArtGradientRadial *gradient = z->gradient;
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int pixstride = (render->n_chan + 1) * (render->depth >> 3);
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int width = render->x1 - x0;
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int n_stops = gradient->n_stops;
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ArtGradientStop *stops = gradient->stops;
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art_u8 *bufp = render->image_buf;
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double fx = gradient->fx;
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double fy = gradient->fy;
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double *affine = gradient->affine;
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double aff0 = affine[0];
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double aff1 = affine[1];
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const double a = z->a;
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const double arecip = 1.0 / a;
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double rad, drad, ddrad;
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ArtGradientSpread spread = gradient->spread;
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dx = x0 * aff0 + y * affine[2] + affine[4] - fx;
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dy = x0 * aff1 + y * affine[3] + affine[5] - fy;
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b = dx * fx + dy * fy;
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db = aff0 * fx + aff1 * fy;
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c = dx * dx + dy * dy;
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dc = 2 * aff0 * dx + aff0 * aff0 + 2 * aff1 * dy + aff1 * aff1;
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ddc = 2 * aff0 * aff0 + 2 * aff1 * aff1;
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rad = b_a * b_a + c * arecip;
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drad = 2 * b_a * db_a + db_a * db_a + dc * arecip;
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ddrad = 2 * db_a * db_a + ddc * arecip;
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for (x = 0; x < width; x++)
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z = b_a + sqrt (rad);
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if (spread == ART_GRADIENT_REPEAT)
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else if (spread == ART_GRADIENT_REFLECT)
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tmp = z - 2 * floor (0.5 * z);
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z = tmp > 1 ? 2 - tmp : tmp;
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art_karbon_render_gradient_setpix (render, bufp, n_stops, stops, z);
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art_karbon_render_gradient_radial_negotiate (ArtImageSource *self, ArtRender *render,
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ArtImageSourceFlags *p_flags,
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int *p_buf_depth, ArtAlphaType *p_alpha)
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self->super.render = art_karbon_render_gradient_radial_render;
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*p_buf_depth = render->depth;
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*p_alpha = ART_ALPHA_PREMUL;
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* art_karbon_render_gradient_radial: Add a radial gradient image source.
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* @render: The render object.
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* @gradient: The radial gradient.
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* Adds the radial gradient @gradient as the image source for rendering
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* in the render object @render.
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art_karbon_render_gradient_radial (ArtRender *render,
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const ArtGradientRadial *gradient,
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ArtFilterLevel level)
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ArtImageSourceGradRad *image_source = art_new (ArtImageSourceGradRad, 1);
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double fx = gradient->fx;
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double fy = gradient->fy;
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image_source->super.super.render = NULL;
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image_source->super.super.done = art_karbon_render_gradient_radial_done;
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image_source->super.negotiate = art_karbon_render_gradient_radial_negotiate;
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image_source->gradient = gradient;
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/* todo: sanitycheck fx, fy? */
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image_source->a = 1 - fx * fx - fy * fy;
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art_render_add_image_source (render, &image_source->super);
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art_render_gradient_conical_done (ArtRenderCallback *self, ArtRender *render)
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art_render_gradient_conical_render (ArtRenderCallback *self, ArtRender *render,
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ArtImageSourceGradCon *z = (ArtImageSourceGradCon *)self;
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const ArtGradientConical *gradient = z->gradient;
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int pixstride = (render->n_chan + 1) * (render->depth >> 3);
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int width = render->x1 - x0;
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int n_stops = gradient->n_stops;
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ArtGradientStop *stops = gradient->stops;
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art_u8 *bufp = render->image_buf;
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double cx = gradient->cx;
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double cy = gradient->cy;
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double r = gradient->r;
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ArtGradientSpread spread = gradient->spread;
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dy = fabs(y) - fabs(cy);
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for (x = 0; x < width; x++)
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dx = fabs(x0 + x) - fabs(cx);
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z = (fabs(dx) + fabs(dy)) / (r);
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if (spread == ART_GRADIENT_REPEAT)
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else if (spread == ART_GRADIENT_REFLECT)
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tmp = z - 2 * floor (0.5 * z);
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z = tmp > 1 ? 2 - tmp : tmp;
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art_karbon_render_gradient_setpix (render, bufp, n_stops, stops, z);
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art_render_gradient_conical_negotiate (ArtImageSource *self, ArtRender *render,
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ArtImageSourceFlags *p_flags,
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int *p_buf_depth, ArtAlphaType *p_alpha)
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self->super.render = art_render_gradient_conical_render;
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*p_buf_depth = render->depth;
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*p_alpha = ART_ALPHA_PREMUL;
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* art_render_gradient_radial: Add a radial gradient image source.
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* @render: The render object.
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* @gradient: The radial gradient.
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* Adds the radial gradient @gradient as the image source for rendering
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* in the render object @render.
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art_karbon_render_gradient_conical (ArtRender *render,
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const ArtGradientConical *gradient,
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ArtFilterLevel level)
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ArtImageSourceGradCon *image_source = art_new (ArtImageSourceGradCon, 1);
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image_source->super.super.render = NULL;
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image_source->super.super.done = art_render_gradient_conical_done;
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image_source->super.negotiate = art_render_gradient_conical_negotiate;
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image_source->gradient = gradient;
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art_render_add_image_source (render, &image_source->super);