forked from KolibriOS/kolibrios
459 lines
11 KiB
C
459 lines
11 KiB
C
#include "fitz.h"
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#include "muxps.h"
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#define MAX_STOPS 256
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enum { SPREAD_PAD, SPREAD_REPEAT, SPREAD_REFLECT };
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/*
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* Parse a list of GradientStop elements.
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* Fill the offset and color arrays, and
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* return the number of stops parsed.
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*/
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struct stop
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{
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float offset;
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float r, g, b, a;
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};
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static int cmp_stop(const void *a, const void *b)
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{
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const struct stop *astop = a;
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const struct stop *bstop = b;
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float diff = astop->offset - bstop->offset;
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if (diff < 0)
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return -1;
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if (diff > 0)
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return 1;
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return 0;
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}
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static inline float lerp(float a, float b, float x)
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{
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return a + (b - a) * x;
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}
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static int
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xps_parse_gradient_stops(xps_context *ctx, char *base_uri, xml_element *node,
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struct stop *stops, int maxcount)
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{
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fz_colorspace *colorspace;
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float sample[8];
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float rgb[3];
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int before, after;
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int count;
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int i;
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/* We may have to insert 2 extra stops when postprocessing */
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maxcount -= 2;
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count = 0;
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while (node && count < maxcount)
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{
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if (!strcmp(xml_tag(node), "GradientStop"))
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{
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char *offset = xml_att(node, "Offset");
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char *color = xml_att(node, "Color");
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if (offset && color)
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{
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stops[count].offset = fz_atof(offset);
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xps_parse_color(ctx, base_uri, color, &colorspace, sample);
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fz_convert_color(colorspace, sample + 1, fz_device_rgb, rgb);
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stops[count].r = rgb[0];
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stops[count].g = rgb[1];
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stops[count].b = rgb[2];
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stops[count].a = sample[0];
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count ++;
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}
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}
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node = xml_next(node);
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}
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if (count == 0)
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{
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fz_warn("gradient brush has no gradient stops");
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stops[0].offset = 0;
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stops[0].r = 0;
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stops[0].g = 0;
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stops[0].b = 0;
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stops[0].a = 1;
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stops[1].offset = 1;
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stops[1].r = 1;
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stops[1].g = 1;
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stops[1].b = 1;
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stops[1].a = 1;
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return 2;
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}
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if (count == maxcount)
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fz_warn("gradient brush exceeded maximum number of gradient stops");
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/* Postprocess to make sure the range of offsets is 0.0 to 1.0 */
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qsort(stops, count, sizeof(struct stop), cmp_stop);
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before = -1;
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after = -1;
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for (i = 0; i < count; i++)
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{
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if (stops[i].offset < 0)
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before = i;
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if (stops[i].offset > 1)
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{
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after = i;
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break;
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}
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}
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/* Remove all stops < 0 except the largest one */
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if (before > 0)
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{
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memmove(stops, stops + before, (count - before) * sizeof(struct stop));
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count -= before;
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}
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/* Remove all stops > 1 except the smallest one */
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if (after >= 0)
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count = after + 1;
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/* Expand single stop to 0 .. 1 */
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if (count == 1)
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{
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stops[1] = stops[0];
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stops[0].offset = 0;
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stops[1].offset = 1;
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return 2;
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}
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/* First stop < 0 -- interpolate value to 0 */
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if (stops[0].offset < 0)
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{
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float d = -stops[0].offset / (stops[1].offset - stops[0].offset);
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stops[0].offset = 0;
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stops[0].r = lerp(stops[0].r, stops[1].r, d);
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stops[0].g = lerp(stops[0].g, stops[1].g, d);
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stops[0].b = lerp(stops[0].b, stops[1].b, d);
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stops[0].a = lerp(stops[0].a, stops[1].a, d);
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}
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/* Last stop > 1 -- interpolate value to 1 */
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if (stops[count-1].offset > 1)
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{
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float d = (1 - stops[count-2].offset) / (stops[count-1].offset - stops[count-2].offset);
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stops[count-1].offset = 1;
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stops[0].r = lerp(stops[count-2].r, stops[count-1].r, d);
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stops[0].g = lerp(stops[count-2].g, stops[count-1].g, d);
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stops[0].b = lerp(stops[count-2].b, stops[count-1].b, d);
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stops[0].a = lerp(stops[count-2].a, stops[count-1].a, d);
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}
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/* First stop > 0 -- insert a duplicate at 0 */
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if (stops[0].offset > 0)
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{
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memmove(stops + 1, stops, count * sizeof(struct stop));
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stops[0] = stops[1];
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stops[0].offset = 0;
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count++;
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}
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/* Last stop < 1 -- insert a duplicate at 1 */
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if (stops[count-1].offset < 1)
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{
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stops[count] = stops[count-1];
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stops[count].offset = 1;
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count++;
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}
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return count;
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}
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static void
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xps_sample_gradient_stops(fz_shade *shade, struct stop *stops, int count)
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{
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float offset, d;
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int i, k;
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k = 0;
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for (i = 0; i < 256; i++)
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{
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offset = i / 255.0f;
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while (k + 1 < count && offset > stops[k+1].offset)
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k++;
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d = (offset - stops[k].offset) / (stops[k+1].offset - stops[k].offset);
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shade->function[i][0] = lerp(stops[k].r, stops[k+1].r, d);
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shade->function[i][1] = lerp(stops[k].g, stops[k+1].g, d);
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shade->function[i][2] = lerp(stops[k].b, stops[k+1].b, d);
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shade->function[i][3] = lerp(stops[k].a, stops[k+1].a, d);
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}
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}
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/*
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* Radial gradients map more or less to Radial shadings.
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* The inner circle is always a point.
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* The outer circle is actually an ellipse,
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* mess with the transform to squash the circle into the right aspect.
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*/
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static void
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xps_draw_one_radial_gradient(xps_context *ctx, fz_matrix ctm,
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struct stop *stops, int count,
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int extend,
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float x0, float y0, float r0,
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float x1, float y1, float r1)
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{
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fz_shade *shade;
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/* TODO: this (and the stuff in pdf_shade) should move to res_shade.c */
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shade = fz_malloc(sizeof(fz_shade));
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shade->refs = 1;
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shade->colorspace = fz_device_rgb;
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shade->bbox = fz_infinite_rect;
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shade->matrix = fz_identity;
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shade->use_background = 0;
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shade->use_function = 1;
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shade->type = FZ_RADIAL;
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shade->extend[0] = extend;
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shade->extend[1] = extend;
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xps_sample_gradient_stops(shade, stops, count);
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shade->mesh_len = 6;
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shade->mesh_cap = 6;
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shade->mesh = fz_calloc(shade->mesh_cap, sizeof(float));
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shade->mesh[0] = x0;
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shade->mesh[1] = y0;
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shade->mesh[2] = r0;
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shade->mesh[3] = x1;
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shade->mesh[4] = y1;
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shade->mesh[5] = r1;
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fz_fill_shade(ctx->dev, shade, ctm, 1);
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fz_drop_shade(shade);
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}
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/*
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* Linear gradients map to Axial shadings.
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*/
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static void
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xps_draw_one_linear_gradient(xps_context *ctx, fz_matrix ctm,
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struct stop *stops, int count,
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int extend,
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float x0, float y0, float x1, float y1)
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{
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fz_shade *shade;
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/* TODO: this (and the stuff in pdf_shade) should move to res_shade.c */
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shade = fz_malloc(sizeof(fz_shade));
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shade->refs = 1;
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shade->colorspace = fz_device_rgb;
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shade->bbox = fz_infinite_rect;
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shade->matrix = fz_identity;
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shade->use_background = 0;
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shade->use_function = 1;
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shade->type = FZ_LINEAR;
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shade->extend[0] = extend;
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shade->extend[1] = extend;
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xps_sample_gradient_stops(shade, stops, count);
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shade->mesh_len = 6;
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shade->mesh_cap = 6;
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shade->mesh = fz_calloc(shade->mesh_cap, sizeof(float));
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shade->mesh[0] = x0;
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shade->mesh[1] = y0;
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shade->mesh[2] = 0;
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shade->mesh[3] = x1;
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shade->mesh[4] = y1;
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shade->mesh[5] = 0;
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fz_fill_shade(ctx->dev, shade, ctm, 1);
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fz_drop_shade(shade);
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}
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/*
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* We need to loop and create many shading objects to account
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* for the Repeat and Reflect SpreadMethods.
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* I'm not smart enough to calculate this analytically
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* so we iterate and check each object until we
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* reach a reasonable limit for infinite cases.
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*/
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static inline float point_inside_circle(float px, float py, float x, float y, float r)
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{
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float dx = px - x;
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float dy = py - y;
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return dx * dx + dy * dy <= r * r;
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}
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static void
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xps_draw_radial_gradient(xps_context *ctx, fz_matrix ctm,
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struct stop *stops, int count,
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xml_element *root, int spread)
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{
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float x0, y0, r0;
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float x1, y1, r1;
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float xrad = 1;
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float yrad = 1;
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float invscale;
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char *center_att = xml_att(root, "Center");
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char *origin_att = xml_att(root, "GradientOrigin");
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char *radius_x_att = xml_att(root, "RadiusX");
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char *radius_y_att = xml_att(root, "RadiusY");
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if (origin_att)
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sscanf(origin_att, "%g,%g", &x0, &y0);
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if (center_att)
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sscanf(center_att, "%g,%g", &x1, &y1);
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if (radius_x_att)
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xrad = fz_atof(radius_x_att);
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if (radius_y_att)
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yrad = fz_atof(radius_y_att);
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/* scale the ctm to make ellipses */
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ctm = fz_concat(fz_scale(1, yrad / xrad), ctm);
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invscale = xrad / yrad;
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y0 = y0 * invscale;
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y1 = y1 * invscale;
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r0 = 0;
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r1 = xrad;
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xps_draw_one_radial_gradient(ctx, ctm, stops, count, 1, x0, y0, r0, x1, y1, r1);
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}
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/*
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* Calculate how many iterations are needed to cover
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* the bounding box.
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*/
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static void
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xps_draw_linear_gradient(xps_context *ctx, fz_matrix ctm,
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struct stop *stops, int count,
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xml_element *root, int spread)
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{
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float x0, y0, x1, y1;
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char *start_point_att = xml_att(root, "StartPoint");
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char *end_point_att = xml_att(root, "EndPoint");
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x0 = y0 = 0;
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x1 = y1 = 1;
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if (start_point_att)
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sscanf(start_point_att, "%g,%g", &x0, &y0);
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if (end_point_att)
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sscanf(end_point_att, "%g,%g", &x1, &y1);
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xps_draw_one_linear_gradient(ctx, ctm, stops, count, 1, x0, y0, x1, y1);
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}
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/*
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* Parse XML tag and attributes for a gradient brush, create color/opacity
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* function objects and call gradient drawing primitives.
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*/
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static void
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xps_parse_gradient_brush(xps_context *ctx, fz_matrix ctm, fz_rect area,
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char *base_uri, xps_resource *dict, xml_element *root,
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void (*draw)(xps_context *, fz_matrix, struct stop *, int, xml_element *, int))
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{
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xml_element *node;
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char *opacity_att;
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char *interpolation_att;
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char *spread_att;
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char *mapping_att;
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char *transform_att;
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xml_element *transform_tag = NULL;
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xml_element *stop_tag = NULL;
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struct stop stop_list[MAX_STOPS];
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int stop_count;
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fz_matrix transform;
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int spread_method;
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opacity_att = xml_att(root, "Opacity");
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interpolation_att = xml_att(root, "ColorInterpolationMode");
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spread_att = xml_att(root, "SpreadMethod");
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mapping_att = xml_att(root, "MappingMode");
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transform_att = xml_att(root, "Transform");
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for (node = xml_down(root); node; node = xml_next(node))
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{
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if (!strcmp(xml_tag(node), "LinearGradientBrush.Transform"))
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transform_tag = xml_down(node);
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if (!strcmp(xml_tag(node), "RadialGradientBrush.Transform"))
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transform_tag = xml_down(node);
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if (!strcmp(xml_tag(node), "LinearGradientBrush.GradientStops"))
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stop_tag = xml_down(node);
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if (!strcmp(xml_tag(node), "RadialGradientBrush.GradientStops"))
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stop_tag = xml_down(node);
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}
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xps_resolve_resource_reference(ctx, dict, &transform_att, &transform_tag, NULL);
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spread_method = SPREAD_PAD;
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if (spread_att)
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{
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if (!strcmp(spread_att, "Pad"))
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spread_method = SPREAD_PAD;
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if (!strcmp(spread_att, "Reflect"))
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spread_method = SPREAD_REFLECT;
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if (!strcmp(spread_att, "Repeat"))
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spread_method = SPREAD_REPEAT;
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}
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transform = fz_identity;
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if (transform_att)
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xps_parse_render_transform(ctx, transform_att, &transform);
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if (transform_tag)
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xps_parse_matrix_transform(ctx, transform_tag, &transform);
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ctm = fz_concat(transform, ctm);
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if (!stop_tag) {
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fz_warn("missing gradient stops tag");
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return;
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}
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stop_count = xps_parse_gradient_stops(ctx, base_uri, stop_tag, stop_list, MAX_STOPS);
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if (stop_count == 0)
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{
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fz_warn("no gradient stops found");
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return;
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}
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xps_begin_opacity(ctx, ctm, area, base_uri, dict, opacity_att, NULL);
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draw(ctx, ctm, stop_list, stop_count, root, spread_method);
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xps_end_opacity(ctx, base_uri, dict, opacity_att, NULL);
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}
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void
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xps_parse_linear_gradient_brush(xps_context *ctx, fz_matrix ctm, fz_rect area,
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char *base_uri, xps_resource *dict, xml_element *root)
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{
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xps_parse_gradient_brush(ctx, ctm, area, base_uri, dict, root, xps_draw_linear_gradient);
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}
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void
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xps_parse_radial_gradient_brush(xps_context *ctx, fz_matrix ctm, fz_rect area,
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char *base_uri, xps_resource *dict, xml_element *root)
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{
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xps_parse_gradient_brush(ctx, ctm, area, base_uri, dict, root, xps_draw_radial_gradient);
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}
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