aab9dafdae
This should possibly save some unneeded conversions. Change-Id: Ice8a186f13a0e61bee260cf910f8a4d0538ef974 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/85542 Tested-by: Jenkins Reviewed-by: Luboš Luňák <l.lunak@collabora.com>
90 lines
3.1 KiB
C++
90 lines
3.1 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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#ifndef INCLUDED_VCL_INC_SCANLINEWRITER_HXX
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#define INCLUDED_VCL_INC_SCANLINEWRITER_HXX
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#include <vcl/bitmap.hxx>
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#include <vcl/BitmapPalette.hxx>
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namespace vcl
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{
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// Write color information for 1, 4 and 8 bit palette bitmap scanlines.
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class ScanlineWriter
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{
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BitmapPalette& maPalette;
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sal_uInt8 const mnColorsPerByte; // number of colors that are stored in one byte
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sal_uInt8 const mnColorBitSize; // number of bits a color takes
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sal_uInt8 const mnColorBitMask; // bit mask used to isolate the color
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sal_uInt8* mpCurrentScanline;
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long mnX;
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public:
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ScanlineWriter(BitmapPalette& aPalette, sal_Int8 nColorsPerByte)
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: maPalette(aPalette)
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, mnColorsPerByte(nColorsPerByte)
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, mnColorBitSize(8 / mnColorsPerByte) // bit size is number of bit in a byte divided by number of colors per byte (8 / 2 = 4 for 4-bit)
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, mnColorBitMask((1 << mnColorBitSize) - 1) // calculate the bit mask from the bit size
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, mpCurrentScanline(nullptr)
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, mnX(0)
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{}
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static std::unique_ptr<ScanlineWriter> Create(sal_uInt16 nBits, BitmapPalette& aPalette)
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{
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switch(nBits)
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{
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case 1:
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return std::make_unique<ScanlineWriter>(aPalette, 8);
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case 4:
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return std::make_unique<ScanlineWriter>(aPalette, 2);
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case 8:
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return std::make_unique<ScanlineWriter>(aPalette, 1);
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default:
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abort();
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}
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}
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void writeRGB(sal_uInt8 nR, sal_uInt8 nG, sal_uInt8 nB)
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{
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// calculate to which index we will write
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long nScanlineIndex = mnX / mnColorsPerByte;
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// calculate the number of shifts to get the color information to the right place
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long nShift = (8 - mnColorBitSize) - ((mnX % mnColorsPerByte) * mnColorBitSize);
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sal_uInt16 nColorIndex = maPalette.GetBestIndex(BitmapColor(nR, nG, nB));
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mpCurrentScanline[nScanlineIndex] &= ~(mnColorBitMask << nShift); // clear
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mpCurrentScanline[nScanlineIndex] |= (nColorIndex & mnColorBitMask) << nShift; // set
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mnX++;
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}
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void nextLine(sal_uInt8* pScanline)
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{
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mnX = 0;
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mpCurrentScanline = pScanline;
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}
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};
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} // namespace vcl
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#endif
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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