drawRingCore()

template<typename PixelT, typename Coord, bool Overwrite>

void fl::gfx::detail::drawRingCore ( Canvas< PixelT > & canvas, const PixelT & color, Coord cx, Coord cy, Coord r, Coord thickness )

inline

Definition at line 734 of file primitives.h.

                                                                                            {
    PixelT* pixels = canvas.pixels;
    int width = canvas.width;
    int height = canvas.height;
 
    fl::i32 cx8 = detail::toFixed8(cx);
    fl::i32 cy8 = detail::toFixed8(cy);
    fl::i32 r8 = detail::toFixed8(r);
    fl::i32 t8 = detail::toFixed8(thickness);
 
    fl::i32 r_ii8 = r8 - 128;
    fl::i32 r_io8 = r8 + 128;
    fl::i32 r_oi8 = r8 + t8 - 128;
    fl::i32 r_oo8 = r8 + t8 + 128;
 
    if (r_ii8 < 0) r_ii8 = 0;
    if (r_io8 < 0) r_io8 = 0;
 
    fl::i32 ii2 = r_ii8 * r_ii8;
    fl::i32 io2 = r_io8 * r_io8;
    fl::i32 oi2 = r_oi8 * r_oi8;
    fl::i32 oo2 = r_oo8 * r_oo8;
 
    fl::i32 inner_band = io2 - ii2;
    fl::i32 outer_band = oo2 - oi2;
 
    int ri = (r_oo8 >> 8) + 1;
    int cxi = cx8 >> 8;
    int cyi = cy8 >> 8;
 
    int xmin = cxi - ri; if (xmin < 0) xmin = 0;
    int xmax = cxi + ri; if (xmax >= width) xmax = width - 1;
    if (xmin > xmax) return;
    if (cyi + ri < 0 || cyi - ri >= height) return;
 
    fl::i32 dx8 = (static_cast<fl::i32>(xmin) << 8) - cx8;
    fl::i32 dx2 = dx8 * dx8;
 
    detail::RingCtx<PixelT> gc;
    gc.xdelta0 = 512 * dx8 + 65536;
    gc.xmin = xmin; gc.xmax = xmax;
    gc.ii2 = ii2; gc.io2 = io2; gc.oi2 = oi2; gc.oo2 = oo2;
    if (inner_band > 0) detail::computeBandShift(inner_band, gc.inner_shift, gc.inner_inv);
    else { gc.inner_shift = 0; gc.inner_inv = 65280u; }
    if (outer_band > 0) detail::computeBandShift(outer_band, gc.outer_shift, gc.outer_inv);
    else { gc.outer_shift = 0; gc.outer_inv = 65280u; }
    gc.color = color;
 
    fl::i32 cyfrac = (static_cast<fl::i32>(cyi) << 8) - cy8;
    fl::i32 d2c = dx2 + cyfrac * cyfrac;
 
    if (cyi >= 0 && cyi < height)
        detail::renderRingRow<PixelT, Overwrite>(pixels, width, cyi, d2c, gc);
 
    fl::i32 botd2 = d2c, botdelta = 512 * cyfrac + 65536;
    fl::i32 topd2 = d2c, topdelta = -512 * cyfrac + 65536;
    botd2 += botdelta; botdelta += 131072;
    topd2 += topdelta; topdelta += 131072;
 
    for (int dy = 1; dy <= ri; ++dy) {
        bool cbot = (botd2 - dx2 <= oo2);
        bool ctop = (topd2 - dx2 <= oo2);
        if (!cbot && !ctop) break;
        int pyb = cyi + dy, pyt = cyi - dy;
        if (cbot && pyb >= 0 && pyb < height)
            detail::renderRingRow<PixelT, Overwrite>(pixels, width, pyb, botd2, gc);
        if (ctop && pyt >= 0 && pyt < height)
            detail::renderRingRow<PixelT, Overwrite>(pixels, width, pyt, topd2, gc);
        botd2 += botdelta; botdelta += 131072;
        topd2 += topdelta; topdelta += 131072;
    }
}

References fl::gfx::detail::RingCtx< PixelT >::color, computeBandShift(), fl::FL_NO_EXCEPT, fl::height, fl::gfx::detail::RingCtx< PixelT >::ii2, fl::gfx::detail::RingCtx< PixelT >::inner_inv, fl::gfx::detail::RingCtx< PixelT >::inner_shift, fl::gfx::detail::RingCtx< PixelT >::io2, fl::gfx::detail::RingCtx< PixelT >::oi2, fl::gfx::detail::RingCtx< PixelT >::oo2, fl::gfx::detail::RingCtx< PixelT >::outer_inv, fl::gfx::detail::RingCtx< PixelT >::outer_shift, renderRingRow(), toFixed8(), fl::width, fl::gfx::detail::RingCtx< PixelT >::xdelta0, fl::gfx::detail::RingCtx< PixelT >::xmax, and fl::gfx::detail::RingCtx< PixelT >::xmin.

Referenced by fl::gfx::drawRing().

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