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7994fc06ad
Imports a new polygon scan converter implementation from the repository at http://cgit.freedesktop.org/~joonas/glitter-paths/ Glitter paths is a stand alone polygon rasteriser derived from David Turner's reimplementation of Tor Anderssons's 15x17 supersampling rasteriser from the Apparition graphics library. The main new feature in this implementation is cheaply choosing per-scan line between doing fully analytical coverage computation for an entire row at a time vs. using a supersampling approach.
144 lines
4.9 KiB
C
144 lines
4.9 KiB
C
/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
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/* cairo - a vector graphics library with display and print output
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*
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* Copyright (c) 2008 M Joonas Pihlaja
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef CAIRO_SPANS_PRIVATE_H
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#define CAIRO_SPANS_PRIVATE_H
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#include "cairo-types-private.h"
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#include "cairo-compiler-private.h"
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/* Number of bits of precision used for alpha. */
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#define CAIRO_SPANS_UNIT_COVERAGE_BITS 8
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#define CAIRO_SPANS_UNIT_COVERAGE ((1 << CAIRO_SPANS_UNIT_COVERAGE_BITS)-1)
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/* A structure representing an open-ended horizontal span of constant
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* pixel coverage. */
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typedef struct _cairo_half_open_span {
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/* The inclusive x-coordinate of the start of the span. */
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int x;
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/* The pixel coverage for the pixels to the right. */
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int coverage;
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} cairo_half_open_span_t;
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/* Span renderer interface. Instances of renderers are provided by
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* surfaces if they want to composite spans instead of trapezoids. */
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typedef struct _cairo_span_renderer cairo_span_renderer_t;
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struct _cairo_span_renderer {
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/* Called to destroy the renderer. */
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cairo_destroy_func_t destroy;
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/* Render the spans on row y of the source by whatever compositing
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* method is required. The function should ignore spans outside
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* the bounding box set by the init() function. */
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cairo_status_t (*render_row)(
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void *abstract_renderer,
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int y,
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const cairo_half_open_span_t *coverages,
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unsigned num_coverages);
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/* Called after all rows have been rendered to perform whatever
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* final rendering step is required. This function is called just
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* once before the renderer is destroyed. */
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cairo_status_t (*finish)(
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void *abstract_renderer);
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/* Private status variable. */
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cairo_status_t status;
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};
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/* Scan converter interface. */
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typedef struct _cairo_scan_converter cairo_scan_converter_t;
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struct _cairo_scan_converter {
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/* Destroy this scan converter. */
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cairo_destroy_func_t destroy;
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/* Add an edge to the converter. */
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cairo_status_t
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(*add_edge)(
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void *abstract_converter,
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cairo_fixed_t x1,
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cairo_fixed_t y1,
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cairo_fixed_t x2,
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cairo_fixed_t y2);
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/* Generates coverage spans for rows for the added edges and calls
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* the renderer function for each row. After generating spans the
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* only valid thing to do with the converter is to destroy it. */
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cairo_status_t
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(*generate)(
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void *abstract_converter,
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cairo_span_renderer_t *renderer);
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/* Private status. Read with _cairo_scan_converter_status(). */
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cairo_status_t status;
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};
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/* Scan converter constructors. */
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cairo_private cairo_scan_converter_t *
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_cairo_tor_scan_converter_create(
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int xmin,
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int ymin,
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int xmax,
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int ymax,
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cairo_fill_rule_t fill_rule);
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/* cairo-spans.c: */
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cairo_private cairo_scan_converter_t *
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_cairo_scan_converter_create_in_error (cairo_status_t error);
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cairo_private cairo_status_t
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_cairo_scan_converter_status (void *abstract_converter);
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cairo_private cairo_status_t
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_cairo_scan_converter_set_error (void *abstract_converter,
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cairo_status_t error);
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cairo_private cairo_span_renderer_t *
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_cairo_span_renderer_create_in_error (cairo_status_t error);
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cairo_private cairo_status_t
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_cairo_span_renderer_status (void *abstract_renderer);
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/* Set the renderer into an error state. This sets all the method
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* pointers except ->destroy() of the renderer to no-op
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* implementations that just return the error status. */
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cairo_private cairo_status_t
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_cairo_span_renderer_set_error (void *abstract_renderer,
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cairo_status_t error);
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cairo_private cairo_status_t
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_cairo_path_fixed_fill_using_spans (
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cairo_operator_t op,
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const cairo_pattern_t *pattern,
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cairo_path_fixed_t *path,
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cairo_surface_t *dst,
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cairo_fill_rule_t fill_rule,
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double tolerance,
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cairo_antialias_t antialias,
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const cairo_composite_rectangles_t *rects);
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#endif /* CAIRO_SPANS_PRIVATE_H */
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