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-rw-r--r--libart_lgpl/art_render_gradient.c716
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diff --git a/libart_lgpl/art_render_gradient.c b/libart_lgpl/art_render_gradient.c
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-/*
- * 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 "config.h"
-#include "art_render_gradient.h"
-
-#include <math.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <assert.h>
-
-/* Hack to find out how to define alloca on different platforms.
- * Modified version of glib/galloca.h.
- */
-
-#ifdef __GNUC__
-/* GCC does the right thing */
-# undef alloca
-# define alloca(size) __builtin_alloca (size)
-#elif defined (HAVE_ALLOCA_H)
-/* a native and working alloca.h is there */
-# include <alloca.h>
-#else /* !__GNUC__ && !HAVE_ALLOCA_H */
-# ifdef _MSC_VER
-# include <malloc.h>
-# define alloca _alloca
-# else /* !_MSC_VER */
-# ifdef _AIX
- #pragma alloca
-# else /* !_AIX */
-# ifndef alloca /* predefined by HP cc +Olibcalls */
-char *alloca ();
-# endif /* !alloca */
-# endif /* !_AIX */
-# endif /* !_MSC_VER */
-#endif /* !__GNUC__ && !HAVE_ALLOCA_H */
-
-#undef DEBUG_SPEW
-
-typedef struct _ArtImageSourceGradLin ArtImageSourceGradLin;
-typedef struct _ArtImageSourceGradRad ArtImageSourceGradRad;
-
-/* The stops will be copied right after this structure */
-struct _ArtImageSourceGradLin {
- ArtImageSource super;
- ArtGradientLinear gradient;
- ArtGradientStop stops[1];
-};
-
-/* The stops will be copied right after this structure */
-struct _ArtImageSourceGradRad {
- ArtImageSource super;
- ArtGradientRadial gradient;
- double a;
- ArtGradientStop stops[1];
-};
-
-#define EPSILON 1e-6
-
-#ifndef MAX
-#define MAX(a, b) (((a) > (b)) ? (a) : (b))
-#endif /* MAX */
-
-#ifndef MIN
-#define MIN(a, b) (((a) < (b)) ? (a) : (b))
-#endif /* MIN */
-
-static void
-art_rgba_gradient_run (art_u8 *buf,
- art_u8 *color1,
- art_u8 *color2,
- int len)
-{
- int i;
- int r, g, b, a;
- int dr, dg, db, da;
-
-#ifdef DEBUG_SPEW
- printf ("gradient run from %3d %3d %3d %3d to %3d %3d %3d %3d in %d pixels\n",
- color1[0], color1[1], color1[2], color1[3],
- color2[0], color2[1], color2[2], color2[3],
- len);
-#endif
-
- r = (color1[0] << 16) + 0x8000;
- g = (color1[1] << 16) + 0x8000;
- b = (color1[2] << 16) + 0x8000;
- a = (color1[3] << 16) + 0x8000;
- dr = ((color2[0] - color1[0]) << 16) / len;
- dg = ((color2[1] - color1[1]) << 16) / len;
- db = ((color2[2] - color1[2]) << 16) / len;
- da = ((color2[3] - color1[3]) << 16) / len;
-
- for (i = 0; i < len; i++)
- {
- *buf++ = (r>>16);
- *buf++ = (g>>16);
- *buf++ = (b>>16);
- *buf++ = (a>>16);
-
- r += dr;
- g += dg;
- b += db;
- a += da;
- }
-}
-
-static void
-calc_color_at (ArtGradientStop *stops,
- int n_stops,
- ArtGradientSpread spread,
- double offset,
- double offset_fraction,
- int favor_start,
- int ix,
- art_u8 *color)
-{
- double off0, off1;
- int j;
-
- if (spread == ART_GRADIENT_PAD)
- {
- if (offset < 0.0)
- {
- color[0] = ART_PIX_8_FROM_MAX (stops[0].color[0]);
- color[1] = ART_PIX_8_FROM_MAX (stops[0].color[1]);
- color[2] = ART_PIX_8_FROM_MAX (stops[0].color[2]);
- color[3] = ART_PIX_8_FROM_MAX (stops[0].color[3]);
- return;
- }
- if (offset >= 1.0)
- {
- color[0] = ART_PIX_8_FROM_MAX (stops[n_stops-1].color[0]);
- color[1] = ART_PIX_8_FROM_MAX (stops[n_stops-1].color[1]);
- color[2] = ART_PIX_8_FROM_MAX (stops[n_stops-1].color[2]);
- color[3] = ART_PIX_8_FROM_MAX (stops[n_stops-1].color[3]);
- return;
- }
- }
-
- if (ix > 0 && ix < n_stops)
- {
- off0 = stops[ix - 1].offset;
- off1 = stops[ix].offset;
- if (fabs (off1 - off0) > EPSILON)
- {
- double interp;
- double o;
- o = offset_fraction;
-
- if ((fabs (o) < EPSILON) && (!favor_start))
- o = 1.0;
- else if ((fabs (o-1.0) < EPSILON) && (favor_start))
- o = 0.0;
-
- /*
- if (offset_fraction == 0.0 && !favor_start)
- offset_fraction = 1.0;
- */
-
- interp = (o - off0) / (off1 - off0);
- for (j = 0; j < 4; 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);
- color[j] = ART_PIX_8_FROM_MAX (z);
- }
- return;
- }
- /* If offsets are too close to safely do the division, just
- pick the ix color. */
- color[0] = ART_PIX_8_FROM_MAX (stops[ix].color[0]);
- color[1] = ART_PIX_8_FROM_MAX (stops[ix].color[1]);
- color[2] = ART_PIX_8_FROM_MAX (stops[ix].color[2]);
- color[3] = ART_PIX_8_FROM_MAX (stops[ix].color[3]);
- return;
- }
-
- printf ("WARNING! bad ix %d in calc_color_at() [internal error]\n", ix);
- assert (0);
-}
-
-static void
-art_render_gradient_linear_render_8 (ArtRenderCallback *self,
- ArtRender *render,
- art_u8 *dest, int y)
-{
- ArtImageSourceGradLin *z = (ArtImageSourceGradLin *)self;
- const ArtGradientLinear *gradient = &(z->gradient);
- int i;
- int width = render->x1 - render->x0;
- int len;
- double offset, d_offset;
- double offset_fraction;
- int next_stop;
- int ix;
- art_u8 color1[4], color2[4];
- int n_stops = gradient->n_stops;
- int extra_stops;
- ArtGradientStop *stops = gradient->stops;
- ArtGradientStop *tmp_stops;
- art_u8 *bufp = render->image_buf;
- ArtGradientSpread spread = gradient->spread;
-
-#ifdef DEBUG_SPEW
- printf ("x1: %d, x2: %d, y: %d\n", render->x0, render->x1, y);
- printf ("spread: %d, stops:", gradient->spread);
- for (i=0;i<n_stops;i++)
- {
- printf ("%f, ", gradient->stops[i].offset);
- }
- printf ("\n");
- printf ("a: %f, b: %f, c: %f\n", gradient->a, gradient->b, gradient->c);
-#endif
-
- offset = render->x0 * gradient->a + y * gradient->b + gradient->c;
- d_offset = gradient->a;
-
- /* We need to force the gradient to extend the whole 0..1 segment,
- because the rest of the code doesn't handle partial gradients
- correctly */
- if ((gradient->stops[0].offset > EPSILON /* == 0.0 */) ||
- (gradient->stops[n_stops-1].offset < (1.0 - EPSILON)))
- {
- extra_stops = 0;
- tmp_stops = stops = alloca (sizeof (ArtGradientStop) * (n_stops + 2));
- if (gradient->stops[0].offset > EPSILON /* 0.0 */)
- {
- memcpy (tmp_stops, gradient->stops, sizeof (ArtGradientStop));
- tmp_stops[0].offset = 0.0;
- tmp_stops += 1;
- extra_stops++;
- }
- memcpy (tmp_stops, gradient->stops, sizeof (ArtGradientStop) * n_stops);
- if (gradient->stops[n_stops-1].offset < (1.0 - EPSILON))
- {
- tmp_stops += n_stops;
- memcpy (tmp_stops, &gradient->stops[n_stops-1], sizeof (ArtGradientStop));
- tmp_stops[0].offset = 1.0;
- extra_stops++;
- }
- n_stops += extra_stops;
-
-
-#ifdef DEBUG_SPEW
- printf ("start/stop modified stops:");
- for (i=0;i<n_stops;i++)
- {
- printf ("%f, ", stops[i].offset);
- }
- printf ("\n");
-#endif
-
- }
-
- if (spread == ART_GRADIENT_REFLECT)
- {
- tmp_stops = stops;
- stops = alloca (sizeof (ArtGradientStop) * n_stops * 2);
- memcpy (stops, tmp_stops, sizeof (ArtGradientStop) * n_stops);
-
- for (i = 0; i< n_stops; i++)
- {
- stops[n_stops * 2 - 1 - i].offset = (1.0 - stops[i].offset / 2.0);
- memcpy (stops[n_stops * 2 - 1 - i].color, stops[i].color, sizeof (stops[i].color));
- stops[i].offset = stops[i].offset / 2.0;
- }
-
- spread = ART_GRADIENT_REPEAT;
- offset = offset / 2.0;
- d_offset = d_offset / 2.0;
-
- n_stops = 2 * n_stops;
-
-#ifdef DEBUG_SPEW
- printf ("reflect modified stops:");
- for (i=0;i<n_stops;i++)
- {
- printf ("%f, ", stops[i].offset);
- }
- printf ("\n");
-#endif
- }
-
- offset_fraction = offset - floor (offset);
-#ifdef DEBUG_SPEW
- printf ("inital offset: %f, fraction: %f d_offset: %f\n", offset, offset_fraction, d_offset);
-#endif
- /* ix is selected so that offset_fraction is
- stops[ix-1] <= offset_fraction <= stops[ix]
- If offset_fraction is equal to one of the edges, ix
- is selected so the the section of the line extending
- in the same direction as d_offset is between ix-1 and ix.
- */
- for (ix = 0; ix < n_stops; ix++)
- if (stops[ix].offset > offset_fraction ||
- (d_offset < 0.0 && fabs (stops[ix].offset - offset_fraction) < EPSILON))
- break;
- if (ix == 0)
- ix = n_stops - 1;
- else if (ix == n_stops)
- ix = n_stops - 1;
-
-#ifdef DEBUG_SPEW
- printf ("Initial ix: %d\n", ix);
-#endif
-
- assert (ix > 0);
- assert (ix < n_stops);
- assert ((stops[ix-1].offset <= offset_fraction + EPSILON) ||
- ((stops[ix].offset > (1.0 - EPSILON)) && (offset_fraction < EPSILON /* == 0.0*/)));
- assert (offset_fraction <= stops[ix].offset);
- /* FIXME: These asserts may be broken, it is for now
- safer to not use them. Should be fixed!
- See bug #121850
- assert ((offset_fraction != stops[ix-1].offset) ||
- (d_offset >= 0.0));
- assert ((offset_fraction != stops[ix].offset) ||
- (d_offset <= 0.0));
- */
-
- while (width > 0)
- {
-#ifdef DEBUG_SPEW
- printf ("ix: %d\n", ix);
- printf ("start offset: %f\n", offset);
-#endif
- calc_color_at (stops, n_stops,
- spread,
- offset,
- offset_fraction,
- (d_offset > -EPSILON),
- ix,
- color1);
-
- if (d_offset > 0)
- next_stop = ix;
- else
- next_stop = ix-1;
-
-#ifdef DEBUG_SPEW
- printf ("next_stop: %d\n", next_stop);
-#endif
- if (fabs (d_offset) > EPSILON)
- {
- double o;
- o = offset_fraction;
-
- if ((fabs (o) <= EPSILON) && (ix == n_stops - 1))
- o = 1.0;
- else if ((fabs (o-1.0) <= EPSILON) && (ix == 1))
- o = 0.0;
-
-#ifdef DEBUG_SPEW
- printf ("o: %f\n", o);
-#endif
- len = (int)floor (fabs ((stops[next_stop].offset - o) / d_offset)) + 1;
- len = MAX (len, 0);
- len = MIN (len, width);
- }
- else
- {
- len = width;
- }
-#ifdef DEBUG_SPEW
- printf ("len: %d\n", len);
-#endif
- if (len > 0)
- {
- offset = offset + (len-1) * d_offset;
- offset_fraction = offset - floor (offset);
-#ifdef DEBUG_SPEW
- printf ("end offset: %f, fraction: %f\n", offset, offset_fraction);
-#endif
- calc_color_at (stops, n_stops,
- spread,
- offset,
- offset_fraction,
- (d_offset < EPSILON),
- ix,
- color2);
-
- art_rgba_gradient_run (bufp,
- color1,
- color2,
- len);
- offset += d_offset;
- offset_fraction = offset - floor (offset);
- }
-
- if (d_offset > 0)
- {
- do
- {
- ix++;
- if (ix == n_stops)
- ix = 1;
- /* Note: offset_fraction can actually be one here on x86 machines that
- does calculations with extended precision, but later rounds to 64bit.
- This happens if the 80bit offset_fraction is larger than the
- largest 64bit double that is less than one.
- */
- }
- while (!((stops[ix-1].offset <= offset_fraction &&
- offset_fraction < stops[ix].offset) ||
- (ix == 1 && offset_fraction > (1.0 - EPSILON))));
- }
- else
- {
- do
- {
- ix--;
- if (ix == 0)
- ix = n_stops - 1;
- }
- while (!((stops[ix-1].offset < offset_fraction &&
- offset_fraction <= stops[ix].offset) ||
- (ix == n_stops - 1 && offset_fraction < EPSILON /* == 0.0*/)));
- }
-
- bufp += 4*len;
- width -= len;
- }
-}
-
-
-/**
- * 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)
-{
- if (render->depth == 8 &&
- render->n_chan == 3)
- {
- self->super.render = art_render_gradient_linear_render_8;
- *p_flags = 0;
- *p_buf_depth = 8;
- *p_alpha = ART_ALPHA_PREMUL;
- return;
- }
-
- 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_alloc (sizeof (ArtImageSourceGradLin) +
- sizeof (ArtGradientStop) * (gradient->n_stops - 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;
-
- /* copy the gradient into the structure */
- image_source->gradient = *gradient;
- image_source->gradient.stops = image_source->stops;
- memcpy (image_source->gradient.stops, gradient->stops, sizeof (ArtGradientStop) * gradient->n_stops);
-
- 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;
- const 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_alloc (sizeof (ArtImageSourceGradRad) +
- sizeof (ArtGradientStop) * (gradient->n_stops - 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;
-
- /* copy the gradient into the structure */
- image_source->gradient = *gradient;
- image_source->gradient.stops = image_source->stops;
- memcpy (image_source->gradient.stops, gradient->stops, sizeof (ArtGradientStop) * gradient->n_stops);
-
- /* todo: sanitycheck fx, fy? */
- image_source->a = 1 - fx * fx - fy * fy;
-
- art_render_add_image_source (render, &image_source->super);
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-20 11:13:43 +0800