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diff --git a/src/sp-gradient.cpp b/src/sp-gradient.cpp
index 3abb91690c9f08512c59f6348ee60cd7d64d661a..84a0a98704315228b655e8b80268a47726069a72 100644 (file)
--- a/src/sp-gradient.cpp
+++ b/src/sp-gradient.cpp
* Authors:
* Lauris Kaplinski <lauris@kaplinski.com>
* bulia byak <buliabyak@users.sf.net>
+ * Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
*
* Copyright (C) 1999-2002 Lauris Kaplinski
* Copyright (C) 2000-2001 Ximian, Inc.
* Copyright (C) 2004 David Turner
+ * Copyright (C) 2009 Jasper van de Gronde
*
* Released under GNU GPL, read the file 'COPYING' for more information
*
gr->color = g_new(guchar, 4 * NCOLORS);
}
- for (guint i = 0; i < gr->vector.stops.size() - 1; i++) {
- guint32 color = gr->vector.stops[i].color.toRGBA32( gr->vector.stops[i].opacity );
- gint r0 = (color >> 24) & 0xff;
- gint g0 = (color >> 16) & 0xff;
- gint b0 = (color >> 8) & 0xff;
- gint a0 = color & 0xff;
- color = gr->vector.stops[i + 1].color.toRGBA32( gr->vector.stops[i + 1].opacity );
- gint r1 = (color >> 24) & 0xff;
- gint g1 = (color >> 16) & 0xff;
- gint b1 = (color >> 8) & 0xff;
- gint a1 = color & 0xff;
- gint o0 = (gint) floor(gr->vector.stops[i].offset * (NCOLORS - 0.001));
- gint o1 = (gint) floor(gr->vector.stops[i + 1].offset * (NCOLORS - 0.001));
- if (o1 > o0) {
- for (int j = o0; j < o1 + 1; j++) {
- gr->color[4 * j + 0] = r0 + DIV_ROUND((j-o0)*(r1-r0),(o1-o0));
- gr->color[4 * j + 1] = g0 + DIV_ROUND((j-o0)*(g1-g0),(o1-o0));
- gr->color[4 * j + 2] = b0 + DIV_ROUND((j-o0)*(b1-b0),(o1-o0));
- gr->color[4 * j + 3] = a0 + DIV_ROUND((j-o0)*(a1-a0),(o1-o0));
+ // This assumes that gr->vector is a zero-order B-spline (box function) approximation of the "true" gradient.
+ // This means that the "true" gradient must be prefiltered using a zero order B-spline and then sampled.
+ // Furthermore, the first element corresponds to offset="0" and the last element to offset="1".
+
+ double remainder[4] = {0,0,0,0};
+ double remainder_for_end[4] = {0,0,0,0}; // Used at the end
+ switch(gr->spread) {
+ case SP_GRADIENT_SPREAD_PAD:
+ remainder[0] = 0.5*gr->vector.stops[0].color.v.c[0]; // Half of the first cell uses the color of the first stop
+ remainder[1] = 0.5*gr->vector.stops[0].color.v.c[1];
+ remainder[2] = 0.5*gr->vector.stops[0].color.v.c[2];
+ remainder[3] = 0.5*gr->vector.stops[0].opacity;
+ remainder_for_end[0] = 0.5*gr->vector.stops[gr->vector.stops.size() - 1].color.v.c[0]; // Half of the first cell uses the color of the last stop
+ remainder_for_end[1] = 0.5*gr->vector.stops[gr->vector.stops.size() - 1].color.v.c[1];
+ remainder_for_end[2] = 0.5*gr->vector.stops[gr->vector.stops.size() - 1].color.v.c[2];
+ remainder_for_end[3] = 0.5*gr->vector.stops[gr->vector.stops.size() - 1].opacity;
+ break;
+ case SP_GRADIENT_SPREAD_REFLECT:
+ case SP_GRADIENT_SPREAD_REPEAT:
+ // These two are handled differently, see below.
+ break;
+ default:
+ g_error("Spread type not supported!");
+ };
+ for (unsigned int i = 0; i < gr->vector.stops.size() - 1; i++) {
+ double r0 = gr->vector.stops[i].color.v.c[0];
+ double g0 = gr->vector.stops[i].color.v.c[1];
+ double b0 = gr->vector.stops[i].color.v.c[2];
+ double a0 = gr->vector.stops[i].opacity;
+ double r1 = gr->vector.stops[i+1].color.v.c[0];
+ double g1 = gr->vector.stops[i+1].color.v.c[1];
+ double b1 = gr->vector.stops[i+1].color.v.c[2];
+ double a1 = gr->vector.stops[i+1].opacity;
+ double o0 = gr->vector.stops[i].offset * (NCOLORS-1);
+ double o1 = gr->vector.stops[i + 1].offset * (NCOLORS-1);
+ unsigned int ob = (unsigned int) floor(o0+.5); // These are the first and last element that might be affected by this interval.
+ unsigned int oe = (unsigned int) floor(o1+.5); // These need to be computed the same to ensure that ob will be covered by the next interval if oe==ob
+
+ if (oe == ob) {
+ // Simple case, this interval starts and stops within one cell
+ // The contribution of this interval is:
+ // (o1-o0)*(c(o0)+c(o1))/2
+ // = (o1-o0)*(c0+c1)/2
+ double dt = 0.5*(o1-o0);
+ remainder[0] += dt*(r0 + r1);
+ remainder[1] += dt*(g0 + g1);
+ remainder[2] += dt*(b0 + b1);
+ remainder[3] += dt*(a0 + a1);
+ } else {
+ // First compute colors for the cells which are fully covered by the current interval.
+ // The prefiltered values are equal to the midpoint of each cell here.
+ // f = (j-o0)/(o1-o0)
+ // = j*(1/(o1-o0)) - o0/(o1-o0)
+ double f = (ob-o0) / (o1-o0);
+ double df = 1. / (o1-o0);
+ for (unsigned int j = ob+1; j < oe; j++) {
+ f += df;
+ gr->color[4 * j + 0] = (unsigned char) floor(255*(r0 + f*(r1-r0)) + .5);
+ gr->color[4 * j + 1] = (unsigned char) floor(255*(g0 + f*(g1-g0)) + .5);
+ gr->color[4 * j + 2] = (unsigned char) floor(255*(b0 + f*(b1-b0)) + .5);
+ gr->color[4 * j + 3] = (unsigned char) floor(255*(a0 + f*(a1-a0)) + .5);
}
+
+ // Now handle the beginning
+ // The contribution of the last point is already in remainder.
+ // The contribution of this point is:
+ // (ob+.5-o0)*(c(o0)+c(ob+.5))/2
+ // = (ob+.5-o0)*c((o0+ob+.5)/2)
+ // = (ob+.5-o0)*(c0+((o0+ob+.5)/2-o0)*df*(c1-c0))
+ // = (ob+.5-o0)*(c0+(ob+.5-o0)*df*(c1-c0)/2)
+ double dt = ob+.5-o0;
+ f = 0.5*dt*df;
+ if (ob==0 && gr->spread==SP_GRADIENT_SPREAD_REFLECT) {
+ // The first half of the first cell is just a mirror image of the second half, so simply multiply it by 2.
+ gr->color[4 * ob + 0] = (unsigned char) floor(2*255*(remainder[0] + dt*(r0 + f*(r1-r0))) + .5);
+ gr->color[4 * ob + 1] = (unsigned char) floor(2*255*(remainder[1] + dt*(g0 + f*(g1-g0))) + .5);
+ gr->color[4 * ob + 2] = (unsigned char) floor(2*255*(remainder[2] + dt*(b0 + f*(b1-b0))) + .5);
+ gr->color[4 * ob + 3] = (unsigned char) floor(2*255*(remainder[3] + dt*(a0 + f*(a1-a0))) + .5);
+ } else if (ob==0 && gr->spread==SP_GRADIENT_SPREAD_REPEAT) {
+ // The first cell is the same as the last cell, so save whatever is in the second half here and deal with the rest later.
+ remainder_for_end[0] = remainder[0] + dt*(r0 + f*(r1-r0));
+ remainder_for_end[1] = remainder[1] + dt*(g0 + f*(g1-g0));
+ remainder_for_end[2] = remainder[2] + dt*(b0 + f*(b1-b0));
+ remainder_for_end[3] = remainder[3] + dt*(a0 + f*(a1-a0));
+ } else {
+ // The first half of the cell was already in remainder.
+ gr->color[4 * ob + 0] = (unsigned char) floor(255*(remainder[0] + dt*(r0 + f*(r1-r0))) + .5);
+ gr->color[4 * ob + 1] = (unsigned char) floor(255*(remainder[1] + dt*(g0 + f*(g1-g0))) + .5);
+ gr->color[4 * ob + 2] = (unsigned char) floor(255*(remainder[2] + dt*(b0 + f*(b1-b0))) + .5);
+ gr->color[4 * ob + 3] = (unsigned char) floor(255*(remainder[3] + dt*(a0 + f*(a1-a0))) + .5);
+ }
+
+ // Now handle the end, which should end up in remainder
+ // The contribution of this point is:
+ // (o1-oe+.5)*(c(o1)+c(oe-.5))/2
+ // = (o1-oe+.5)*c((o1+oe-.5)/2)
+ // = (o1-oe+.5)*(c0+((o1+oe-.5)/2-o0)*df*(c1-c0))
+ dt = o1-oe+.5;
+ f = (0.5*(o1+oe-.5)-o0)*df;
+ remainder[0] = dt*(r0 + f*(r1-r0));
+ remainder[1] = dt*(g0 + f*(g1-g0));
+ remainder[2] = dt*(b0 + f*(b1-b0));
+ remainder[3] = dt*(a0 + f*(a1-a0));
}
}
+ switch(gr->spread) {
+ case SP_GRADIENT_SPREAD_PAD:
+ gr->color[4 * (NCOLORS-1) + 0] = (unsigned char) floor(255*(remainder[0]+remainder_for_end[0]) + .5);
+ gr->color[4 * (NCOLORS-1) + 1] = (unsigned char) floor(255*(remainder[1]+remainder_for_end[1]) + .5);
+ gr->color[4 * (NCOLORS-1) + 2] = (unsigned char) floor(255*(remainder[2]+remainder_for_end[2]) + .5);
+ gr->color[4 * (NCOLORS-1) + 3] = (unsigned char) floor(255*(remainder[3]+remainder_for_end[3]) + .5);
+ break;
+ case SP_GRADIENT_SPREAD_REFLECT:
+ // The second half is the same as the first half, so multiply by 2.
+ gr->color[4 * (NCOLORS-1) + 0] = (unsigned char) floor(2*255*remainder[0] + .5);
+ gr->color[4 * (NCOLORS-1) + 1] = (unsigned char) floor(2*255*remainder[1] + .5);
+ gr->color[4 * (NCOLORS-1) + 2] = (unsigned char) floor(2*255*remainder[2] + .5);
+ gr->color[4 * (NCOLORS-1) + 3] = (unsigned char) floor(2*255*remainder[3] + .5);
+ break;
+ case SP_GRADIENT_SPREAD_REPEAT:
+ // The second half is the same as the second half of the first cell (which was saved in remainder_for_end).
+ gr->color[0] = gr->color[4 * (NCOLORS-1) + 0] = (unsigned char) floor(255*(remainder[0]+remainder_for_end[0]) + .5);
+ gr->color[1] = gr->color[4 * (NCOLORS-1) + 1] = (unsigned char) floor(255*(remainder[1]+remainder_for_end[1]) + .5);
+ gr->color[2] = gr->color[4 * (NCOLORS-1) + 2] = (unsigned char) floor(255*(remainder[2]+remainder_for_end[2]) + .5);
+ gr->color[3] = gr->color[4 * (NCOLORS-1) + 3] = (unsigned char) floor(255*(remainder[3]+remainder_for_end[3]) + .5);
+ break;
+ }
}
/**
static void sp_lineargradient_init(SPLinearGradient *lg)
{
lg->x1.unset(SVGLength::PERCENT, 0.0, 0.0);
- lg->y1.unset(SVGLength::PERCENT, 0.5, 0.5);
+ lg->y1.unset(SVGLength::PERCENT, 0.0, 0.0);
lg->x2.unset(SVGLength::PERCENT, 1.0, 1.0);
- lg->y2.unset(SVGLength::PERCENT, 0.5, 0.5);
+ lg->y2.unset(SVGLength::PERCENT, 0.0, 0.0);
}
/**
object->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SP_ATTR_Y1:
- lg->y1.readOrUnset(value, SVGLength::PERCENT, 0.5, 0.5);
+ lg->y1.readOrUnset(value, SVGLength::PERCENT, 0.0, 0.0);
object->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SP_ATTR_X2:
object->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SP_ATTR_Y2:
- lg->y2.readOrUnset(value, SVGLength::PERCENT, 0.5, 0.5);
+ lg->y2.readOrUnset(value, SVGLength::PERCENT, 0.0, 0.0);
object->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
default: