agg-rust 1.1.0

Pure Rust port of Anti-Grain Geometry (AGG) 2.6 - high quality 2D vector graphics rendering
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133

// flash_rasterizer.cpp headless reproduction. Mirrors the Rust pixel-compare
// scene: read shape 0 from art/shapes.txt, fill it with the compound rasterizer
// (solid per-style palette), stroke the outlines, and draw the help text. The
// non-deterministic benchmark timing prefix is omitted so output is reproducible.
#include <cmath>
#include <vector>

#include "agg_basics.h"
#include "agg_rendering_buffer.h"
#include "agg_rasterizer_scanline_aa.h"
#include "agg_rasterizer_compound_aa.h"
#include "agg_scanline_u.h"
#include "agg_scanline_bin.h"
#include "agg_renderer_scanline.h"
#include "agg_conv_curve.h"
#include "agg_conv_transform.h"
#include "agg_conv_stroke.h"
#include "agg_span_allocator.h"
#include "agg_gsv_text.h"
#include "agg_pixfmt_rgba.h"

#include "common.h"
#include "flash_shape.h"

static void flash_palette(agg::rgba8* colors) {
    agg::msvc_rand rng;
    for (int i = 0; i < 100; ++i) {
        // Sequence the RNG into named temporaries so the three bytes map to
        // (r, g, b) in that order. The original example wrote
        // rgba8(rand(), rand(), rand(), 230) directly, but C++ leaves argument
        // evaluation order unspecified (MSVC evaluates right-to-left), which
        // would silently assign the first byte to blue. Assigning in logical
        // r,g,b order matches the example's intent and the Rust port.
        unsigned r = rng.next() & 0xFF;
        unsigned g = rng.next() & 0xFF;
        unsigned b = rng.next() & 0xFF;
        colors[i] = agg::rgba8(r, g, b, 230);
        colors[i].premultiply();
    }
}

int render_flash_rasterizer(unsigned w, unsigned h,
                            const std::vector<double>& params, const char* out) {
    typedef agg::pixfmt_bgra32 pixfmt;
    typedef agg::renderer_base<pixfmt> renderer_base;
    typedef agg::renderer_scanline_aa_solid<renderer_base> renderer_solid;

    int shape_index = params.size() > 0 ? (int)params[0] : 0;
    double user_scale = params.size() > 0 ? std::max(0.001, std::fabs(params[0])) : 1.0;
    // Extended-state params use params[0] as a shape index, not scale.
    if (params.size() >= 7) { shape_index = (int)params[0]; user_scale = 1.0; }
    else shape_index = 0;

    agg::compound_shape shape;
    if (!shape.open(headless::asset_path("shapes.txt").c_str())) {
        fprintf(stderr, "flash_rasterizer: failed to open shapes.txt\n");
        return 1;
    }
    for (int i = 0; i <= shape_index; ++i) {
        if (!shape.read_next()) break;
    }

    agg::rgba8 colors[100];
    flash_palette(colors);

    headless::canvas cv(w, h, 4);
    pixfmt pixf(cv.rbuf);
    renderer_base rb(pixf);
    rb.clear(agg::rgba8(255, 255, 242, 255)); // rgba(1.0, 1.0, 0.95)

    agg::trans_affine mtx = shape.compute_viewport(w, h);

    // Fill via the compound rasterizer (solid per-style colors).
    agg::rasterizer_compound_aa<agg::rasterizer_sl_clip_dbl> rasc;
    agg::scanline_u8 sl;
    agg::scanline_bin sl_bin;
    agg::span_allocator<agg::rgba8> alloc;
    agg::solid_styles style_handler(colors);

    rasc.clip_box(0, 0, w, h);
    rasc.layer_order(agg::layer_direct);
    rasc.reset();

    agg::conv_curve<agg::path_storage> fill_curve(shape.shape_path());
    fill_curve.approximation_scale(std::max(1.0, user_scale));
    agg::conv_transform<agg::conv_curve<agg::path_storage> > trans_shape(fill_curve, mtx);

    for (unsigned i = 0; i < shape.paths(); ++i) {
        const agg::path_style& st = shape.style(i);
        if (st.left_fill >= 0 || st.right_fill >= 0) {
            rasc.styles(st.left_fill, st.right_fill);
            rasc.add_path(trans_shape, st.path_id);
        }
    }
    agg::render_scanlines_compound(rasc, sl, sl_bin, rb, alloc, style_handler);

    // Strokes.
    agg::rasterizer_scanline_aa<agg::rasterizer_sl_clip_dbl> ras;
    renderer_solid ren(rb);
    ras.clip_box(0, 0, w, h);
    agg::conv_curve<agg::path_storage> stroke_curve(shape.shape_path());
    stroke_curve.approximation_scale(std::max(1.0, user_scale));
    agg::conv_transform<agg::conv_curve<agg::path_storage> > trans_stroke(stroke_curve, mtx);
    agg::conv_stroke<agg::conv_transform<agg::conv_curve<agg::path_storage> > > stroke(trans_stroke);
    stroke.width(std::sqrt(user_scale));
    stroke.line_join(agg::round_join);
    stroke.line_cap(agg::round_cap);
    for (unsigned i = 0; i < shape.paths(); ++i) {
        const agg::path_style& st = shape.style(i);
        if (st.line >= 0) {
            ras.reset();
            ras.add_path(stroke, st.path_id);
            ren.color(agg::rgba8(0, 0, 0, 128));
            agg::render_scanlines(ras, sl, ren);
        }
    }

    // Help text (timer prefix omitted for deterministic output).
    agg::gsv_text t;
    t.size(8.0);
    t.flip(true);
    t.start_point(10.0, 20.0);
    t.text("Space: Next Shape\n\n+/- : ZoomIn/ZoomOut (with respect to the mouse pointer)");
    agg::conv_stroke<agg::gsv_text> ts(t);
    ts.width(1.6);
    ts.line_cap(agg::round_cap);
    ras.reset();
    ras.add_path(ts);
    ren.color(agg::rgba8(0, 0, 0, 255));
    agg::render_scanlines(ras, sl, ren);

    return headless::write_raw(out, pixf, w, h) ? 0 : 1;
}