DenysMedvid/pdf2htmlEX
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Improve DrawingTracer::stroke() by break path into steps.

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This commit is contained in:
Duan Yao 2014-06-18 17:58:05 +08:00
parent a57b61731d
commit f705a98581
1 changed files with 60 additions and 7 deletions
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67
src/DrawingTracer.cc
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@ -10,6 +10,9 @@
#include "util/math.h"
#include "DrawingTracer.h"
//#define DT_DEBUG(x) (x)
#define DT_DEBUG(x)
namespace pdf2htmlEX
{
@ -128,14 +131,63 @@ void DrawingTracer::stroke(GfxState * state)
{
if (!param.process_covered_text)
return;
// TODO
// 1. if stroke extents is large, break the path into pieces and handle each of them;
// 2. if the line width is small, could just ignore the path?
do_path(state, state->getPath());
DT_DEBUG(printf("DrawingTracer::stroke\n"));
cairo_set_line_width(cairo, state->getLineWidth());
double sbox[4];
cairo_stroke_extents(cairo, sbox, sbox + 1, sbox + 2, sbox + 3);
draw_non_char_bbox(state, sbox);
// GfxPath is broken into steps, each step makes up a cairo path and its bbox is used for covering test.
// TODO
// 1. path steps that are not vertical or horizontal lines may still falsely "cover" many chars,
// can we slice those steps further?
// 2. if the line width is small, can we just ignore the path?
GfxPath * path = state->getPath();
for (int i = 0; i < path->getNumSubpaths(); ++i) {
GfxSubpath * subpath = path->getSubpath(i);
if (subpath->getNumPoints() <= 0)
continue;
double x = subpath->getX(0);
double y = subpath->getY(0);
//p: loop cursor; j: next point index
int p =1, j = 1;
int n = subpath->getNumPoints();
while (p <= n) {
cairo_new_path(cairo);
cairo_move_to(cairo, x, y);
if (subpath->getCurve(j)) {
x = subpath->getX(j+2);
y = subpath->getY(j+2);
cairo_curve_to(cairo,
subpath->getX(j), subpath->getY(j),
subpath->getX(j+1), subpath->getY(j+1),
x, y);
p += 3;
} else {
x = subpath->getX(j);
y = subpath->getY(j);
cairo_line_to(cairo, x, y);
++p;
}
DT_DEBUG(printf("DrawingTracer::stroke:new box:\n"));
double sbox[4];
cairo_stroke_extents(cairo, sbox, sbox + 1, sbox + 2, sbox + 3);
if (sbox[0] != sbox[2] && sbox[1] != sbox[3])
draw_non_char_bbox(state, sbox);
else
DT_DEBUG(printf("DrawingTracer::stroke:zero box!\n"));
if (p == n)
{
if (subpath->isClosed())
j = 0; // if sub path is closed, go back to starting point
else
break;
}
else
j = p;
}
}
}
void DrawingTracer::fill(GfxState * state, bool even_odd)
@ -157,6 +209,7 @@ void DrawingTracer::draw_non_char_bbox(GfxState * state, double * bbox)
if(bbox_intersect(cbox, bbox, bbox))
{
transform_bbox_by_ctm(bbox);
DT_DEBUG(printf("DrawingTracer::draw_non_char_bbox:[%f,%f,%f,%f]\n", bbox[0],bbox[1],bbox[2],bbox[3]));
if (on_non_char_drawn)
on_non_char_drawn(bbox);
}