122 lines
3.7 KiB
C++
122 lines
3.7 KiB
C++
//-----------------------------------------------------------------------------
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// A rendering backend that draws on a Cairo surface.
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//
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// Copyright 2016 whitequark
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//-----------------------------------------------------------------------------
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#include <cairo.h>
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#include "solvespace.h"
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namespace SolveSpace {
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void CairoRenderer::OutputStart() {
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cairo_save(context);
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RgbaColor bgColor = lighting.backgroundColor;
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cairo_rectangle(context, 0.0, 0.0, camera.width, camera.height);
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cairo_set_source_rgba(context, bgColor.redF(), bgColor.greenF(), bgColor.blueF(),
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bgColor.alphaF());
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cairo_fill(context);
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cairo_translate(context, camera.width / 2.0, camera.height / 2.0);
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// Avoid pixel boundaries; when not using antialiasing, we would otherwise
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// get numerically unstable output.
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cairo_translate(context, 0.1, 0.1);
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cairo_set_line_join(context, CAIRO_LINE_JOIN_ROUND);
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cairo_set_line_cap(context, CAIRO_LINE_CAP_ROUND);
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}
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void CairoRenderer::OutputEnd() {
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FinishPath();
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cairo_restore(context);
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cairo_surface_flush(cairo_get_target(context));
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}
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void CairoRenderer::SelectStroke(hStroke hcs) {
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if(current.hcs.v == hcs.v) return;
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FinishPath();
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Stroke *stroke = strokes.FindById(hcs);
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current.hcs = hcs;
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RgbaColor color = stroke->color;
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std::vector<double> dashes = StipplePatternDashes(stroke->stipplePattern);
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for(double &dash : dashes) {
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dash *= stroke->StippleScalePx(camera);
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}
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cairo_set_line_width(context, stroke->WidthPx(camera));
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cairo_set_dash(context, dashes.data(), dashes.size(), 0);
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cairo_set_source_rgba(context, color.redF(), color.greenF(), color.blueF(),
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color.alphaF());
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if(antialias) {
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cairo_set_antialias(context, CAIRO_ANTIALIAS_GRAY);
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} else {
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cairo_set_antialias(context, CAIRO_ANTIALIAS_NONE);
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}
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}
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void CairoRenderer::MoveTo(Vector p) {
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Point2d pos;
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cairo_get_current_point(context, &pos.x, &pos.y);
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if(cairo_has_current_point(context) && pos.Equals(p.ProjectXy())) return;
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FinishPath();
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cairo_move_to(context, p.x, p.y);
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}
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void CairoRenderer::FinishPath() {
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if(!cairo_has_current_point(context)) return;
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cairo_stroke(context);
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}
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void CairoRenderer::OutputBezier(const SBezier &b, hStroke hcs) {
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SelectStroke(hcs);
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Vector c, n = Vector::From(0, 0, 1);
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double r;
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if(b.deg == 1) {
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MoveTo(b.ctrl[0]);
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cairo_line_to(context,
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b.ctrl[1].x, b.ctrl[1].y);
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} else if(b.IsCircle(n, &c, &r)) {
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MoveTo(b.ctrl[0]);
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double theta0 = atan2(b.ctrl[0].y - c.y, b.ctrl[0].x - c.x),
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theta1 = atan2(b.ctrl[2].y - c.y, b.ctrl[2].x - c.x),
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dtheta = WRAP_SYMMETRIC(theta1 - theta0, 2*PI);
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if(dtheta > 0) {
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cairo_arc(context,
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c.x, c.y, r, theta0, theta1);
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} else {
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cairo_arc_negative(context,
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c.x, c.y, r, theta0, theta1);
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}
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} else if(b.deg == 3 && !b.IsRational()) {
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MoveTo(b.ctrl[0]);
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cairo_curve_to(context,
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b.ctrl[1].x, b.ctrl[1].y,
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b.ctrl[2].x, b.ctrl[2].y,
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b.ctrl[3].x, b.ctrl[3].y);
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} else {
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OutputBezierAsNonrationalCubic(b, hcs);
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}
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}
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void CairoRenderer::OutputTriangle(const STriangle &tr) {
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FinishPath();
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current.hcs = {};
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RgbaColor color = tr.meta.color;
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cairo_set_source_rgba(context, color.redF(), color.greenF(), color.blueF(),
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color.alphaF());
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cairo_set_antialias(context, CAIRO_ANTIALIAS_NONE);
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cairo_move_to(context, tr.a.x, tr.a.y);
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cairo_line_to(context, tr.b.x, tr.b.y);
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cairo_line_to(context, tr.c.x, tr.c.y);
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cairo_fill(context);
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}
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}
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