Differential D9686 Diff 24995 libs/image/KisPrecisePaintDeviceWrapper.h

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libs/image/KisPrecisePaintDeviceWrapper.h

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		1		/*
		2		* Copyright (c) 2018 Dmitry Kazakov <dimula73@gmail.com>
		3		*
		4		* This program is free software; you can redistribute it and/or modify
		5		* it under the terms of the GNU General Public License as published by
		6		* the Free Software Foundation; either version 2 of the License, or
		7		* (at your option) any later version.
		8		*
		9		* This program is distributed in the hope that it will be useful,
		10		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		11		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		12		* GNU General Public License for more details.
		13		*
		14		* You should have received a copy of the GNU General Public License
		15		* along with this program; if not, write to the Free Software
		16		* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
		17		*/
		18
		19		#ifndef KISPRECISEPAINTDEVICEWRAPPER_H
		20		#define KISPRECISEPAINTDEVICEWRAPPER_H
		21
		22		#include <QScopedPointer>
		23
		24		#include "kis_types.h"
		25		#include "kritaimage_export.h"
		26
		27		class KoColorSpace;
		28		class QRegion;
		29
		30		/**
		31		* A special wrapper class for a paint device that allows working with
		32		* parts of the source paint device as if it had higher bit depth.
		33		*
		34		* For example, you have an RGBA8 paint device, but you want all the
		35		* blending happen in higher bit depth. You wrap your paint device (source paint
		36		* device) into KisPrecisePaintDeviceWrapper, and the wrapper creates a temporary
		37		* device (precise paint device) in RGBA16 colorspace. The you work with this precise
		38		* paint device as usual, uploading and downloading pixel data to/from the source
		39		* paint device using readRect() and writeRect()
		40		*
		41		* If the source device is already "precise", that is having the bit depth higher than
		42		* 8 bit per channel, no temporary device is created. All the operations are forwarded
		43		* directly to the source device
		44		*
		45		* Example:
		46		*
		47		* \code{.cpp}
		48		* // initialize the wrapper with the source device,
		49		* // it creates a precise device if needed
		50		* KisPrecisePaintDeviceWrapper wrapper(sourceDevice);
		51		*
		52		* // download the data from the source device, the operation
		53		* // might be cached due to keepRectsHistory option
		54		* wrapper.readRect(accessRect);
		55		*
		56		* // start modifying the data
		57		* KisPainter gc(wrapper.preciseDevice());
		58		*
		59		* // low opacity might be handled incorrectly in the original
		60		* // color space, but we work in a precise one!
		61		* gc.setOpacity(1);
		62		* gc.bitBlt(accessRect.topLeft(), someOtherDevice, accessRect);
		63		*
		64		* // ... repeat multiple times if needed ...
		65		*
		66		* // upload the data back to the original source device
		67		* wrapper.writeRect(accessRect);
		68		* \endcode
		69		*
		70		*/
		71
		72		class KRITAIMAGE_EXPORT KisPrecisePaintDeviceWrapper
		73		{
		74		public:
		75		/**
		76		* Create a wrapper, attach it to \p device and create a temporary precise
		77		* paint device if needed. The temporary device is created iff the source
		78		* device has 8 bit bit-depth.
		79		*
		80		* \param device source device
		81		* \param keepRectsHistory shown how many rects in readRect() should be cached
		82		*/
		83		KisPrecisePaintDeviceWrapper(KisPaintDeviceSP device, int keepRectsHistory = 50);
		84		~KisPrecisePaintDeviceWrapper();
		85
		86		/**
		87		* \return the color space of preciseDevice()
		88		*/
		89		const KoColorSpace* preciseColorSpace() const;
		90
		91		/**
		92		* \return the source device attached to the wrapper
		93		*/
		94		KisPaintDeviceSP sourceDevice() const;
		95
		96		/**
		97		* \return the precise device. If the source device color space is "precise", then
		98		* there is no separate precise device, and the original device is returned
		99		*/
		100		KisPaintDeviceSP preciseDevice() const;
		101
		102		/**
		103		* \return the region of the source device that is guaranteed to be cached by
		104		* previous calls to readRect(). If one asks for reading a cached rect,
		105		* it is not read and just reused.
		106		*/
		107		QRegion cachedRegion() const;
		108
		109		/**
		110		* Reset the region of the cached data from the source paint device
		111		*/
		112		void resetCachedRegion();
		113
		114		/**
		115		* Read rect \p rc from the source device and upload it into the precision device.
		116		* If rounding correction is not used, the function does nothing.
		117		*/
		118		void readRect(const QRect &rc);
		119
		120		/**
		121		* Write rect \p rc from the precision to source device
		122		* If rounding correction is not used, the function does nothing.
		123		*/
		124		void writeRect(const QRect &rc);
		125
		126		/**
		127		* \see readRect()
		128		*/
		129		void readRects(const QVector<QRect> &rects);
		130
		131		/**
		132		* \see writeRect()
		133		*/
		134		void writeRects(const QVector<QRect> &rects);
		135
		136		private:
		137		struct Private;
		138		const QScopedPointer<Private> m_d;
		139		};
		140
		141		#endif // KISPRECISEPAINTDEVICEWRAPPER_H