35e409e926
Found via `codespell -q 3 -S *.ts,thirdparty, -L appy,ba,inbetween,inout,pevent,possibile,upto`
98 lines
3.3 KiB
C++
98 lines
3.3 KiB
C++
#pragma once
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#ifndef RUNSMAP_H
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#define RUNSMAP_H
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#include "traster.h"
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//*********************************************************************************************************
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// Run Maps
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//*********************************************************************************************************
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/*!
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The RunsMapP is an auxiliary raster greymap type used to store run-length
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information
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about an image.
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Not every image pixel has valid information. Only pixels corresponding to
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run headers do, and those include the position of the next run header.
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This means that users must always iterate from the beginning of a line to get
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valid
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data.
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The following coding is adopted to extract the run length from the run
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headers:
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\li We'll use the last 2 bits only in the headers. With these, we can cover
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directly
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those runs up to 4 pixels length.
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\li When the length >=4, we require that one byte is taken in the run to store
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the length
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up to 256 pixels.
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\li When the length >= 256, we take 4 additional bytes to store the length
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(which this time
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could go up to billions).
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Observe that the runsmap supports a symmetrical representation, useful
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to traverse runs both forward and backwards. This means that 2 headers are
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provided for each run, at the opposite ends (unless the run is 1 pixel-width).
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*/
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class RunsMap final : public TRasterT<TPixelGR8> {
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public:
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RunsMap(int lx, int ly) : TRasterT<TPixelGR8>(lx, ly) { clear(); }
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const UCHAR &runHeader(int x, int y) const { return pixels(y)[x].value; }
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UCHAR &runHeader(int x, int y) { return pixels(y)[x].value; }
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TUINT32 runLength(const TPixelGR8 *run, bool reversed = false) const;
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TUINT32 runLength(int x, int y, bool reversed = false) const {
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return runLength(pixels(y) + x, reversed);
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}
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public:
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void setRunLength(TPixelGR8 *run, TUINT32 length);
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void setRunLength(int x, int y, TUINT32 length) {
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setRunLength(pixels(y) + x, length);
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}
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};
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//---------------------------------------------------------------------------------------------
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#ifdef _WIN32
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template class DV_EXPORT_API TSmartPointerT<RunsMap>;
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#endif
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class RunsMapP final : public TSmartPointerT<RunsMap> {
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public:
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RunsMapP() {}
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RunsMapP(int lx, int ly) : TSmartPointerT<RunsMap>(new RunsMap(lx, ly)) {}
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RunsMapP(const TDimension &d)
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: TSmartPointerT<RunsMap>(new RunsMap(d.lx, d.ly)) {}
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};
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//---------------------------------------------------------------------------------------------
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template <typename Pixel, typename PixelSelector>
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void buildRunsMap(RunsMapP &runsMap, const TRasterPT<Pixel> &ras,
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const PixelSelector &selector) {
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// Traverse the raster, extracting run lengths
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int y, ly = ras->getLy();
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for (y = 0; y < ly; ++y) {
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Pixel *lineStart = (Pixel *)ras->pixels(y),
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*lineEnd = lineStart + ras->getLx();
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Pixel *pix, *runStart;
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typename PixelSelector::value_type colorIndex;
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for (pix = runStart = lineStart, colorIndex = selector.value(*pix);
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pix < lineEnd; ++pix)
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if (selector.value(*pix) != colorIndex) {
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runsMap->setRunLength(runStart - lineStart, y, pix - runStart);
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runStart = pix;
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colorIndex = selector.value(*pix);
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}
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runsMap->setRunLength(runStart - lineStart, y, pix - runStart);
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}
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}
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#endif // RUNSMAP_H
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