--- /dev/null
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * art_rgba_svp.c: A slightly modified version of art_rgb_svp to render into rgba buffer
+ *
+ * This program 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 program 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 program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Authors:
+ * Raph Levien <raph@acm.org>
+ * Lauris Kaplinski <lauris@ariman.ee>
+ *
+ * Copyright (C) 1998 Raph Levien
+ *
+ */
+
+#define SP_ART_RGBA_SVP_C
+
+/* Render a sorted vector path into an RGBA buffer. */
+
+#include <libart_lgpl/art_misc.h>
+#include <libart_lgpl/art_svp.h>
+#include <libart_lgpl/art_svp_render_aa.h>
+#include <libart_lgpl/art_rgb.h>
+
+#include "art_rgba_svp.h"
+
+static void art_rgba_fill_run (art_u8 * linebuf, art_u8 r, art_u8 g, art_u8 b, int n);
+static void art_rgba_run_alpha (art_u8 * linebuf, art_u8 r, art_u8 g, art_u8 b, int alpha, int n);
+
+typedef struct _ArtRgbaSVPAlphaData ArtRgbaSVPAlphaData;
+
+struct _ArtRgbaSVPAlphaData {
+ int alphatab[256];
+ art_u8 r, g, b, alpha;
+ art_u8 *buf;
+ int rowstride;
+ int x0, x1;
+};
+
+static void
+art_rgba_svp_alpha_callback (void *callback_data, int y,
+ int start, ArtSVPRenderAAStep *steps, int n_steps)
+{
+ ArtRgbaSVPAlphaData *data = callback_data;
+ art_u8 *linebuf;
+ int run_x0, run_x1;
+ art_u32 running_sum = start;
+ int x0, x1;
+ int k;
+ art_u8 r, g, b;
+ int *alphatab;
+ int alpha;
+
+ linebuf = data->buf;
+ x0 = data->x0;
+ x1 = data->x1;
+
+ r = data->r;
+ g = data->g;
+ b = data->b;
+ alphatab = data->alphatab;
+
+ if (n_steps > 0)
+ {
+ run_x1 = steps[0].x;
+ if (run_x1 > x0)
+ {
+ alpha = (running_sum >> 16) & 0xff;
+ if (alpha)
+ art_rgba_run_alpha (linebuf,
+ r, g, b, alphatab[alpha],
+ run_x1 - x0);
+ }
+
+ /* render the steps into tmpbuf */
+ for (k = 0; k < n_steps - 1; k++)
+ {
+ running_sum += steps[k].delta;
+ run_x0 = run_x1;
+ run_x1 = steps[k + 1].x;
+ if (run_x1 > run_x0)
+ {
+ alpha = (running_sum >> 16) & 0xff;
+ if (alpha)
+ art_rgba_run_alpha (linebuf + (run_x0 - x0) * 4,
+ r, g, b, alphatab[alpha],
+ run_x1 - run_x0);
+ }
+ }
+ running_sum += steps[k].delta;
+ if (x1 > run_x1)
+ {
+ alpha = (running_sum >> 16) & 0xff;
+ if (alpha)
+ art_rgba_run_alpha (linebuf + (run_x1 - x0) * 4,
+ r, g, b, alphatab[alpha],
+ x1 - run_x1);
+ }
+ }
+ else
+ {
+ alpha = (running_sum >> 16) & 0xff;
+ if (alpha)
+ art_rgba_run_alpha (linebuf,
+ r, g, b, alphatab[alpha],
+ x1 - x0);
+ }
+
+ data->buf += data->rowstride;
+}
+
+static void
+art_rgba_svp_alpha_opaque_callback (void *callback_data, int y,
+ int start,
+ ArtSVPRenderAAStep *steps, int n_steps)
+{
+ ArtRgbaSVPAlphaData *data = callback_data;
+ art_u8 *linebuf;
+ int run_x0, run_x1;
+ art_u32 running_sum = start;
+ int x0, x1;
+ int k;
+ art_u8 r, g, b;
+ int *alphatab;
+ int alpha;
+
+ linebuf = data->buf;
+ x0 = data->x0;
+ x1 = data->x1;
+
+ r = data->r;
+ g = data->g;
+ b = data->b;
+ alphatab = data->alphatab;
+
+ if (n_steps > 0)
+ {
+ run_x1 = steps[0].x;
+ if (run_x1 > x0)
+ {
+ alpha = running_sum >> 16;
+ if (alpha)
+ {
+ if (alpha >= 255)
+ art_rgba_fill_run (linebuf,
+ r, g, b,
+ run_x1 - x0);
+ else
+ art_rgba_run_alpha (linebuf,
+ r, g, b, alphatab[alpha],
+ run_x1 - x0);
+ }
+ }
+
+ /* render the steps into tmpbuf */
+ for (k = 0; k < n_steps - 1; k++)
+ {
+ running_sum += steps[k].delta;
+ run_x0 = run_x1;
+ run_x1 = steps[k + 1].x;
+ if (run_x1 > run_x0)
+ {
+ alpha = running_sum >> 16;
+ if (alpha)
+ {
+ if (alpha >= 255)
+ art_rgba_fill_run (linebuf + (run_x0 - x0) * 4,
+ r, g, b,
+ run_x1 - run_x0);
+ else
+ art_rgba_run_alpha (linebuf + (run_x0 - x0) * 4,
+ r, g, b, alphatab[alpha],
+ run_x1 - run_x0);
+ }
+ }
+ }
+ running_sum += steps[k].delta;
+ if (x1 > run_x1)
+ {
+ alpha = running_sum >> 16;
+ if (alpha)
+ {
+ if (alpha >= 255)
+ art_rgba_fill_run (linebuf + (run_x1 - x0) * 4,
+ r, g, b,
+ x1 - run_x1);
+ else
+ art_rgba_run_alpha (linebuf + (run_x1 - x0) * 4,
+ r, g, b, alphatab[alpha],
+ x1 - run_x1);
+ }
+ }
+ }
+ else
+ {
+ alpha = running_sum >> 16;
+ if (alpha)
+ {
+ if (alpha >= 255)
+ art_rgba_fill_run (linebuf,
+ r, g, b,
+ x1 - x0);
+ else
+ art_rgba_run_alpha (linebuf,
+ r, g, b, alphatab[alpha],
+ x1 - x0);
+ }
+ }
+
+ data->buf += data->rowstride;
+}
+
+/**
+ * gnome_print_art_rgba_svp_alpha: Alpha-composite sorted vector path over RGBA buffer.
+ * @svp: The source sorted vector path.
+ * @x0: Left coordinate of destination rectangle.
+ * @y0: Top coordinate of destination rectangle.
+ * @x1: Right coordinate of destination rectangle.
+ * @y1: Bottom coordinate of destination rectangle.
+ * @rgba: Color in 0xRRGGBBAA format.
+ * @buf: Destination RGB buffer.
+ * @rowstride: Rowstride of @buf buffer.
+ * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing.
+ *
+ * Renders the shape specified with @svp over the @buf RGB buffer.
+ * @x1 - @x0 specifies the width, and @y1 - @y0 specifies the height,
+ * of the rectangle rendered. The new pixels are stored starting at
+ * the first byte of @buf. Thus, the @x0 and @y0 parameters specify
+ * an offset within @svp, and may be tweaked as a way of doing
+ * integer-pixel translations without fiddling with @svp itself.
+ *
+ * The @rgba argument specifies the color for the rendering. Pixels of
+ * entirely 0 winding number are left untouched. Pixels of entirely
+ * 1 winding number have the color @rgba composited over them (ie,
+ * are replaced by the red, green, blue components of @rgba if the alpha
+ * component is 0xff). Pixels of intermediate coverage are interpolated
+ * according to the rule in @alphagamma, or default to linear if
+ * @alphagamma is NULL.
+ **/
+void
+gnome_print_art_rgba_svp_alpha (const ArtSVP *svp,
+ int x0, int y0, int x1, int y1,
+ art_u32 rgba,
+ art_u8 *buf, int rowstride,
+ ArtAlphaGamma *alphagamma)
+{
+ ArtRgbaSVPAlphaData data;
+ int r, g, b, alpha;
+ int i;
+ int a, da;
+
+ r = rgba >> 24;
+ g = (rgba >> 16) & 0xff;
+ b = (rgba >> 8) & 0xff;
+ alpha = rgba & 0xff;
+
+ data.r = r;
+ data.g = g;
+ data.b = b;
+ data.alpha = alpha;
+
+ a = 0x8000;
+ da = (alpha * 66051 + 0x80) >> 8; /* 66051 equals 2 ^ 32 / (255 * 255) */
+
+ for (i = 0; i < 256; i++)
+ {
+ data.alphatab[i] = a >> 16;
+ a += da;
+ }
+
+ data.buf = buf;
+ data.rowstride = rowstride;
+ data.x0 = x0;
+ data.x1 = x1;
+ if (alpha == 255)
+ art_svp_render_aa (svp, x0, y0, x1, y1, art_rgba_svp_alpha_opaque_callback,
+ &data);
+ else
+ art_svp_render_aa (svp, x0, y0, x1, y1, art_rgba_svp_alpha_callback, &data);
+}
+
+static void
+art_rgba_fill_run (art_u8 * buf, art_u8 r, art_u8 g, art_u8 b, int n)
+{
+ int i;
+
+ for (i = 0; i < n; i++) {
+ * buf++ = r;
+ * buf++ = g;
+ * buf++ = b;
+ * buf++ = 255;
+ }
+}
+
+/* fixme: this */
+
+static void
+art_rgba_run_alpha (art_u8 * buf, art_u8 r, art_u8 g, art_u8 b, int alpha, int n)
+{
+ int i;
+ int br, bg, bb, ba;
+ int cr, cg, cb;
+
+ for (i = 0; i < n; i++) {
+ br = * (buf + 0);
+ bg = * (buf + 1);
+ bb = * (buf + 2);
+ ba = * (buf + 3);
+
+ cr = (br * ba + 0x80) >> 8;
+ cg = (bg * ba + 0x80) >> 8;
+ cb = (bb * ba + 0x80) >> 8;
+
+ * buf++ = cr + (((r - cr) * alpha + 0x80) >> 8);
+ * buf++ = cg + (((g - cg) * alpha + 0x80) >> 8);
+ * buf++ = cb + (((b - cb) * alpha + 0x80) >> 8);
+ * buf++ = ba + (((255 - ba) * alpha + 0x80) >> 8);
+ }
+}
+
+
projects / rrdtool.git / blobdiff