227 lines
9.0 KiB
C
227 lines
9.0 KiB
C
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/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2020 - Raw Material Software Limited
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JUCE is an open source library subject to commercial or open-source
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licensing.
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By using JUCE, you agree to the terms of both the JUCE 6 End-User License
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Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).
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End User License Agreement: www.juce.com/juce-6-licence
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Privacy Policy: www.juce.com/juce-privacy-policy
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Or: You may also use this code under the terms of the GPL v3 (see
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www.gnu.org/licenses).
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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A table of horizontal scan-line segments - used for rasterising Paths.
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@see Path, Graphics
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@tags{Graphics}
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*/
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class JUCE_API EdgeTable
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{
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public:
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//==============================================================================
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/** Creates an edge table containing a path.
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A table is created with a fixed vertical range, and only sections of the path
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which lie within this range will be added to the table.
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@param clipLimits only the region of the path that lies within this area will be added
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@param pathToAdd the path to add to the table
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@param transform a transform to apply to the path being added
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*/
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EdgeTable (Rectangle<int> clipLimits,
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const Path& pathToAdd,
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const AffineTransform& transform);
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/** Creates an edge table containing a rectangle. */
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explicit EdgeTable (Rectangle<int> rectangleToAdd);
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/** Creates an edge table containing a rectangle. */
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explicit EdgeTable (Rectangle<float> rectangleToAdd);
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/** Creates an edge table containing a rectangle list. */
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explicit EdgeTable (const RectangleList<int>& rectanglesToAdd);
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/** Creates an edge table containing a rectangle list. */
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explicit EdgeTable (const RectangleList<float>& rectanglesToAdd);
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/** Creates a copy of another edge table. */
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EdgeTable (const EdgeTable&);
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/** Copies from another edge table. */
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EdgeTable& operator= (const EdgeTable&);
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/** Destructor. */
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~EdgeTable();
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//==============================================================================
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void clipToRectangle (Rectangle<int> r);
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void excludeRectangle (Rectangle<int> r);
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void clipToEdgeTable (const EdgeTable&);
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void clipLineToMask (int x, int y, const uint8* mask, int maskStride, int numPixels);
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bool isEmpty() noexcept;
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const Rectangle<int>& getMaximumBounds() const noexcept { return bounds; }
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void translate (float dx, int dy) noexcept;
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/** Scales all the alpha-levels in the table by the given multiplier. */
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void multiplyLevels (float factor);
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/** Reduces the amount of space the table has allocated.
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This will shrink the table down to use as little memory as possible - useful for
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read-only tables that get stored and re-used for rendering.
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*/
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void optimiseTable();
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//==============================================================================
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/** Iterates the lines in the table, for rendering.
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This function will iterate each line in the table, and call a user-defined class
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to render each pixel or continuous line of pixels that the table contains.
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@param iterationCallback this templated class must contain the following methods:
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@code
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inline void setEdgeTableYPos (int y);
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inline void handleEdgeTablePixel (int x, int alphaLevel) const;
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inline void handleEdgeTablePixelFull (int x) const;
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inline void handleEdgeTableLine (int x, int width, int alphaLevel) const;
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inline void handleEdgeTableLineFull (int x, int width) const;
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@endcode
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(these don't necessarily have to be 'const', but it might help it go faster)
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*/
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template <class EdgeTableIterationCallback>
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void iterate (EdgeTableIterationCallback& iterationCallback) const noexcept
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{
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const int* lineStart = table;
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for (int y = 0; y < bounds.getHeight(); ++y)
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{
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const int* line = lineStart;
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lineStart += lineStrideElements;
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int numPoints = line[0];
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if (--numPoints > 0)
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{
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int x = *++line;
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jassert ((x / scale) >= bounds.getX() && (x / scale) < bounds.getRight());
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int levelAccumulator = 0;
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iterationCallback.setEdgeTableYPos (bounds.getY() + y);
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while (--numPoints >= 0)
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{
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const int level = *++line;
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jassert (isPositiveAndBelow (level, scale));
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const int endX = *++line;
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jassert (endX >= x);
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const int endOfRun = (endX / scale);
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if (endOfRun == (x / scale))
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{
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// small segment within the same pixel, so just save it for the next
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// time round..
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levelAccumulator += (endX - x) * level;
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}
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else
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{
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// plot the fist pixel of this segment, including any accumulated
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// levels from smaller segments that haven't been drawn yet
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levelAccumulator += (0x100 - (x & 0xff)) * level;
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levelAccumulator /= scale;
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x /= scale;
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if (levelAccumulator > 0)
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{
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if (levelAccumulator >= 255)
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iterationCallback.handleEdgeTablePixelFull (x);
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else
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iterationCallback.handleEdgeTablePixel (x, levelAccumulator);
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}
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// if there's a run of similar pixels, do it all in one go..
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if (level > 0)
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{
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jassert (endOfRun <= bounds.getRight());
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const int numPix = endOfRun - ++x;
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if (numPix > 0)
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iterationCallback.handleEdgeTableLine (x, numPix, level);
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}
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// save the bit at the end to be drawn next time round the loop.
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levelAccumulator = (endX & 0xff) * level;
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}
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x = endX;
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}
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levelAccumulator /= scale;
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if (levelAccumulator > 0)
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{
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x /= scale;
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jassert (x >= bounds.getX() && x < bounds.getRight());
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if (levelAccumulator >= 255)
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iterationCallback.handleEdgeTablePixelFull (x);
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else
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iterationCallback.handleEdgeTablePixel (x, levelAccumulator);
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}
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}
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}
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}
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private:
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//==============================================================================
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static constexpr auto defaultEdgesPerLine = 32;
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static constexpr auto scale = 256;
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//==============================================================================
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// table line format: number of points; point0 x, point0 levelDelta, point1 x, point1 levelDelta, etc
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struct LineItem
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{
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int x, level;
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bool operator< (const LineItem& other) const noexcept { return x < other.x; }
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};
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HeapBlock<int> table;
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Rectangle<int> bounds;
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int maxEdgesPerLine, lineStrideElements;
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bool needToCheckEmptiness = true;
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void allocate();
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void clearLineSizes() noexcept;
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void addEdgePoint (int x, int y, int winding);
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void addEdgePointPair (int x1, int x2, int y, int winding);
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void remapTableForNumEdges (int newNumEdgesPerLine);
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void remapWithExtraSpace (int numPointsNeeded);
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void intersectWithEdgeTableLine (int y, const int* otherLine);
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void clipEdgeTableLineToRange (int* line, int x1, int x2) noexcept;
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void sanitiseLevels (bool useNonZeroWinding) noexcept;
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static void copyEdgeTableData (int* dest, int destLineStride, const int* src, int srcLineStride, int numLines) noexcept;
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JUCE_LEAK_DETECTOR (EdgeTable)
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};
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} // namespace juce
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