+++ /dev/null
-/*
- * art_render_gradient.c: Gradient image source for modular rendering.
- *
- * Libart_LGPL - library of basic graphic primitives
- * Copyright (C) 2000 Raph Levien
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- *
- * Authors: Raph Levien <raph@acm.org>
- * Alexander Larsson <alla@lysator.liu.se>
- */
-
-#include <math.h>
-
-#include "art_misc.h"
-#include "art_alphagamma.h"
-#include "art_filterlevel.h"
-
-#include "art_render.h"
-#include "art_render_gradient.h"
-
-typedef struct _ArtImageSourceGradLin ArtImageSourceGradLin;
-typedef struct _ArtImageSourceGradRad ArtImageSourceGradRad;
-
-struct _ArtImageSourceGradLin {
- ArtImageSource super;
- const ArtGradientLinear *gradient;
-};
-
-struct _ArtImageSourceGradRad {
- ArtImageSource super;
- const ArtGradientRadial *gradient;
- double a;
-};
-
-#define EPSILON 1e-6
-
-/**
- * art_render_gradient_setpix: Set a gradient pixel.
- * @render: The render object.
- * @dst: Pointer to destination (where to store pixel).
- * @n_stops: Number of stops in @stops.
- * @stops: The stops for the gradient.
- * @offset: The offset.
- *
- * @n_stops must be > 0.
- *
- * Sets a gradient pixel, storing it at @dst.
- **/
-static void
-art_render_gradient_setpix (ArtRender *render,
- art_u8 *dst,
- int n_stops, ArtGradientStop *stops,
- double offset)
-{
- int ix;
- int j;
- double off0, off1;
- int n_ch = render->n_chan + 1;
-
- for (ix = 0; ix < n_stops; ix++)
- if (stops[ix].offset > offset)
- break;
- /* stops[ix - 1].offset < offset < stops[ix].offset */
- if (ix > 0 && ix < n_stops)
- {
- off0 = stops[ix - 1].offset;
- off1 = stops[ix].offset;
- if (fabs (off1 - off0) > EPSILON)
- {
- double interp;
-
- interp = (offset - off0) / (off1 - off0);
- for (j = 0; j < n_ch; j++)
- {
- int z0, z1;
- int z;
- z0 = stops[ix - 1].color[j];
- z1 = stops[ix].color[j];
- z = floor (z0 + (z1 - z0) * interp + 0.5);
- if (render->buf_depth == 8)
- dst[j] = ART_PIX_8_FROM_MAX (z);
- else /* (render->buf_depth == 16) */
- ((art_u16 *)dst)[j] = z;
- }
- return;
- }
- }
- else if (ix == n_stops)
- ix--;
-
- for (j = 0; j < n_ch; j++)
- {
- int z;
- z = stops[ix].color[j];
- if (render->buf_depth == 8)
- dst[j] = ART_PIX_8_FROM_MAX (z);
- else /* (render->buf_depth == 16) */
- ((art_u16 *)dst)[j] = z;
- }
-}
-
-static void
-art_render_gradient_linear_done (ArtRenderCallback *self, ArtRender *render)
-{
- art_free (self);
-}
-
-static void
-art_render_gradient_linear_render (ArtRenderCallback *self, ArtRender *render,
- art_u8 *dest, int y)
-{
- ArtImageSourceGradLin *z = (ArtImageSourceGradLin *)self;
- const ArtGradientLinear *gradient = z->gradient;
- int pixstride = (render->n_chan + 1) * (render->depth >> 3);
- int x;
- int width = render->x1 - render->x0;
- double offset, d_offset;
- double actual_offset;
- int n_stops = gradient->n_stops;
- ArtGradientStop *stops = gradient->stops;
- art_u8 *bufp = render->image_buf;
- ArtGradientSpread spread = gradient->spread;
-
- offset = render->x0 * gradient->a + y * gradient->b + gradient->c;
- d_offset = gradient->a;
-
- for (x = 0; x < width; x++)
- {
- if (spread == ART_GRADIENT_PAD)
- actual_offset = offset;
- else if (spread == ART_GRADIENT_REPEAT)
- actual_offset = offset - floor (offset);
- else /* (spread == ART_GRADIENT_REFLECT) */
- {
- double tmp;
-
- tmp = offset - 2 * floor (0.5 * offset);
- actual_offset = tmp > 1 ? 2 - tmp : tmp;
- }
- art_render_gradient_setpix (render, bufp, n_stops, stops, actual_offset);
- offset += d_offset;
- bufp += pixstride;
- }
-}
-
-static void
-art_render_gradient_linear_negotiate (ArtImageSource *self, ArtRender *render,
- ArtImageSourceFlags *p_flags,
- int *p_buf_depth, ArtAlphaType *p_alpha)
-{
- self->super.render = art_render_gradient_linear_render;
- *p_flags = 0;
- *p_buf_depth = render->depth;
- *p_alpha = ART_ALPHA_PREMUL;
-}
-
-/**
- * art_render_gradient_linear: Add a linear gradient image source.
- * @render: The render object.
- * @gradient: The linear gradient.
- *
- * Adds the linear gradient @gradient as the image source for rendering
- * in the render object @render.
- **/
-void
-art_render_gradient_linear (ArtRender *render,
- const ArtGradientLinear *gradient,
- ArtFilterLevel level)
-{
- ArtImageSourceGradLin *image_source = art_new (ArtImageSourceGradLin, 1);
-
- image_source->super.super.render = NULL;
- image_source->super.super.done = art_render_gradient_linear_done;
- image_source->super.negotiate = art_render_gradient_linear_negotiate;
-
- image_source->gradient = gradient;
-
- art_render_add_image_source (render, &image_source->super);
-}
-
-static void
-art_render_gradient_radial_done (ArtRenderCallback *self, ArtRender *render)
-{
- art_free (self);
-}
-
-static void
-art_render_gradient_radial_render (ArtRenderCallback *self, ArtRender *render,
- art_u8 *dest, int y)
-{
- ArtImageSourceGradRad *z = (ArtImageSourceGradRad *)self;
- const ArtGradientRadial *gradient = z->gradient;
- int pixstride = (render->n_chan + 1) * (render->depth >> 3);
- int x;
- int x0 = render->x0;
- int width = render->x1 - x0;
- int n_stops = gradient->n_stops;
- ArtGradientStop *stops = gradient->stops;
- art_u8 *bufp = render->image_buf;
- double fx = gradient->fx;
- double fy = gradient->fy;
- double dx, dy;
- double *affine = gradient->affine;
- double aff0 = affine[0];
- double aff1 = affine[1];
- const double a = z->a;
- const double arecip = 1.0 / a;
- double b, db;
- double c, dc, ddc;
- double b_a, db_a;
- double rad, drad, ddrad;
-
- dx = x0 * aff0 + y * affine[2] + affine[4] - fx;
- dy = x0 * aff1 + y * affine[3] + affine[5] - fy;
- b = dx * fx + dy * fy;
- db = aff0 * fx + aff1 * fy;
- c = dx * dx + dy * dy;
- dc = 2 * aff0 * dx + aff0 * aff0 + 2 * aff1 * dy + aff1 * aff1;
- ddc = 2 * aff0 * aff0 + 2 * aff1 * aff1;
-
- b_a = b * arecip;
- db_a = db * arecip;
-
- rad = b_a * b_a + c * arecip;
- drad = 2 * b_a * db_a + db_a * db_a + dc * arecip;
- ddrad = 2 * db_a * db_a + ddc * arecip;
-
- for (x = 0; x < width; x++)
- {
- double z;
-
- if (rad > 0)
- z = b_a + sqrt (rad);
- else
- z = b_a;
- art_render_gradient_setpix (render, bufp, n_stops, stops, z);
- bufp += pixstride;
- b_a += db_a;
- rad += drad;
- drad += ddrad;
- }
-}
-
-static void
-art_render_gradient_radial_negotiate (ArtImageSource *self, ArtRender *render,
- ArtImageSourceFlags *p_flags,
- int *p_buf_depth, ArtAlphaType *p_alpha)
-{
- self->super.render = art_render_gradient_radial_render;
- *p_flags = 0;
- *p_buf_depth = render->depth;
- *p_alpha = ART_ALPHA_PREMUL;
-}
-
-/**
- * art_render_gradient_radial: Add a radial gradient image source.
- * @render: The render object.
- * @gradient: The radial gradient.
- *
- * Adds the radial gradient @gradient as the image source for rendering
- * in the render object @render.
- **/
-void
-art_render_gradient_radial (ArtRender *render,
- const ArtGradientRadial *gradient,
- ArtFilterLevel level)
-{
- ArtImageSourceGradRad *image_source = art_new (ArtImageSourceGradRad, 1);
- double fx = gradient->fx;
- double fy = gradient->fy;
-
- image_source->super.super.render = NULL;
- image_source->super.super.done = art_render_gradient_radial_done;
- image_source->super.negotiate = art_render_gradient_radial_negotiate;
-
- image_source->gradient = gradient;
- /* todo: sanitycheck fx, fy? */
- image_source->a = 1 - fx * fx - fy * fy;
-
- art_render_add_image_source (render, &image_source->super);
-}
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