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/*
==============================================================================
This file is part of the JUCE library.
Copyright (c) 2015 - ROLI Ltd.
Permission is granted to use this software under the terms of either:
a) the GPL v2 (or any later version)
b) the Affero GPL v3
Details of these licenses can be found at: www.gnu.org/licenses
JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
------------------------------------------------------------------------------
To release a closed-source product which uses JUCE, commercial licenses are
available: visit www.juce.com for more information.
==============================================================================
*/
#ifndef JUCE_EDGETABLE_H_INCLUDED
#define JUCE_EDGETABLE_H_INCLUDED
//==============================================================================
/**
A table of horizontal scan-line segments - used for rasterising Paths.
@see Path, Graphics
*/
class JUCE_API EdgeTable
{
public:
//==============================================================================
/** Creates an edge table containing a path.
A table is created with a fixed vertical range, and only sections of the path
which lie within this range will be added to the table.
@param clipLimits only the region of the path that lies within this area will be added
@param pathToAdd the path to add to the table
@param transform a transform to apply to the path being added
*/
EdgeTable (const Rectangle<int>& clipLimits,
const Path& pathToAdd,
const AffineTransform& transform);
/** Creates an edge table containing a rectangle. */
explicit EdgeTable (const Rectangle<int>& rectangleToAdd);
/** Creates an edge table containing a rectangle list. */
explicit EdgeTable (const RectangleList<int>& rectanglesToAdd);
/** Creates an edge table containing a rectangle list. */
explicit EdgeTable (const RectangleList<float>& rectanglesToAdd);
/** Creates an edge table containing a rectangle. */
explicit EdgeTable (const Rectangle<float>& rectangleToAdd);
/** Creates a copy of another edge table. */
EdgeTable (const EdgeTable&);
/** Copies from another edge table. */
EdgeTable& operator= (const EdgeTable&);
/** Destructor. */
~EdgeTable();
//==============================================================================
void clipToRectangle (const Rectangle<int>& r);
void excludeRectangle (const Rectangle<int>& r);
void clipToEdgeTable (const EdgeTable&);
void clipLineToMask (int x, int y, const uint8* mask, int maskStride, int numPixels);
bool isEmpty() noexcept;
const Rectangle<int>& getMaximumBounds() const noexcept { return bounds; }
void translate (float dx, int dy) noexcept;
/** Scales all the alpha-levels in the table by the given multiplier. */
void multiplyLevels (float factor);
/** Reduces the amount of space the table has allocated.
This will shrink the table down to use as little memory as possible - useful for
read-only tables that get stored and re-used for rendering.
*/
void optimiseTable();
//==============================================================================
/** Iterates the lines in the table, for rendering.
This function will iterate each line in the table, and call a user-defined class
to render each pixel or continuous line of pixels that the table contains.
@param iterationCallback this templated class must contain the following methods:
@code
inline void setEdgeTableYPos (int y);
inline void handleEdgeTablePixel (int x, int alphaLevel) const;
inline void handleEdgeTablePixelFull (int x) const;
inline void handleEdgeTableLine (int x, int width, int alphaLevel) const;
inline void handleEdgeTableLineFull (int x, int width) const;
@endcode
(these don't necessarily have to be 'const', but it might help it go faster)
*/
template <class EdgeTableIterationCallback>
void iterate (EdgeTableIterationCallback& iterationCallback) const noexcept
{
const int* lineStart = table;
for (int y = 0; y < bounds.getHeight(); ++y)
{
const int* line = lineStart;
lineStart += lineStrideElements;
int numPoints = line[0];
if (--numPoints > 0)
{
int x = *++line;
jassert ((x >> 8) >= bounds.getX() && (x >> 8) < bounds.getRight());
int levelAccumulator = 0;
iterationCallback.setEdgeTableYPos (bounds.getY() + y);
while (--numPoints >= 0)
{
const int level = *++line;
jassert (isPositiveAndBelow (level, (int) 256));
const int endX = *++line;
jassert (endX >= x);
const int endOfRun = (endX >> 8);
if (endOfRun == (x >> 8))
{
// small segment within the same pixel, so just save it for the next
// time round..
levelAccumulator += (endX - x) * level;
}
else
{
// plot the fist pixel of this segment, including any accumulated
// levels from smaller segments that haven't been drawn yet
levelAccumulator += (0x100 - (x & 0xff)) * level;
levelAccumulator >>= 8;
x >>= 8;
if (levelAccumulator > 0)
{
if (levelAccumulator >= 255)
iterationCallback.handleEdgeTablePixelFull (x);
else
iterationCallback.handleEdgeTablePixel (x, levelAccumulator);
}
// if there's a run of similar pixels, do it all in one go..
if (level > 0)
{
jassert (endOfRun <= bounds.getRight());
const int numPix = endOfRun - ++x;
if (numPix > 0)
iterationCallback.handleEdgeTableLine (x, numPix, level);
}
// save the bit at the end to be drawn next time round the loop.
levelAccumulator = (endX & 0xff) * level;
}
x = endX;
}
levelAccumulator >>= 8;
if (levelAccumulator > 0)
{
x >>= 8;
jassert (x >= bounds.getX() && x < bounds.getRight());
if (levelAccumulator >= 255)
iterationCallback.handleEdgeTablePixelFull (x);
else
iterationCallback.handleEdgeTablePixel (x, levelAccumulator);
}
}
}
}
private:
//==============================================================================
// table line format: number of points; point0 x, point0 levelDelta, point1 x, point1 levelDelta, etc
struct LineItem
{
int x, level;
bool operator< (const LineItem& other) const noexcept { return x < other.x; }
};
HeapBlock<int> table;
Rectangle<int> bounds;
int maxEdgesPerLine, lineStrideElements;
bool needToCheckEmptiness;
void allocate();
void clearLineSizes() noexcept;
void addEdgePoint (int x, int y, int winding);
void addEdgePointPair (int x1, int x2, int y, int winding);
void remapTableForNumEdges (int newNumEdgesPerLine);
void intersectWithEdgeTableLine (int y, const int* otherLine);
void clipEdgeTableLineToRange (int* line, int x1, int x2) noexcept;
void sanitiseLevels (bool useNonZeroWinding) noexcept;
static void copyEdgeTableData (int* dest, int destLineStride, const int* src, int srcLineStride, int numLines) noexcept;
JUCE_LEAK_DETECTOR (EdgeTable)
};
#endif // JUCE_EDGETABLE_H_INCLUDED
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