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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#pragma once
#include <sal/log.hxx>
#include <basegfx/polygon/b2dpolypolygon.hxx>
#include <tools/gen.hxx>
#include <tools/degree.hxx>
#include <vcl/devicecoordinate.hxx>
#include <vcl/glyphitem.hxx>
#include <vcl/dllapi.h>
class LogicalFontInstance;
namespace vcl::text { class ImplLayoutArgs; }
namespace vcl::font { class PhysicalFontFace; }
class SalGraphics;
class GlyphItem;
// all positions/widths are in font units
// one exception: drawposition is in pixel units
// Unfortunately there is little documentation to help implementors of
// new classes derived from SalLayout ("layout engines"), and the code
// and data structures are far from obvious.
// For instance, I *think* the important virtual functions in the
// layout engines are called in this order:
// * InitFont()
// * LayoutText()
// * AdjustLayout(), any number of times (but presumably
// usually not at all or just once)
// * Optionally, DrawText()
// Functions that just return information like GetTexWidth() and
// FillDXArray() are called after LayoutText() and before DrawText().
// Another important questions is which parts of an ImplLayoutArgs can
// be changed by callers between LayoutText() and AdjustLayout()
// calls. It probably makes sense only if one assumes that the "string
// related inputs" part are not changed after LayoutText().
// But why use the same ImplLayoutArgs structure as parameter for both
// LayoutText() and AdjustLayout() in the first place? And why
// duplicate some of the fields in both SalLayout and ImplLayoutArgs
// (mnMinCharPos, mnEndCharPos, mnLayoutFlags==mnFlags,
// mnOrientation)? Lost in history...
class VCL_DLLPUBLIC SalLayout
{
public:
virtual ~SalLayout();
// used by upper layers
Point& DrawBase() { return maDrawBase; }
const Point& DrawBase() const { return maDrawBase; }
Point& DrawOffset() { return maDrawOffset; }
const Point& DrawOffset() const { return maDrawOffset; }
Point GetDrawPosition( const Point& rRelative = Point(0,0) ) const;
virtual bool LayoutText( vcl::text::ImplLayoutArgs&, const SalLayoutGlyphsImpl* ) = 0; // first step of layouting
virtual void AdjustLayout( vcl::text::ImplLayoutArgs& ); // adjusting after fallback etc.
virtual void InitFont() const {}
virtual void DrawText( SalGraphics& ) const = 0;
int GetUnitsPerPixel() const { return mnUnitsPerPixel; }
Degree10 GetOrientation() const { return mnOrientation; }
// methods using string indexing
virtual sal_Int32 GetTextBreak(DeviceCoordinate nMaxWidth, DeviceCoordinate nCharExtra, int nFactor) const = 0;
virtual DeviceCoordinate FillDXArray( std::vector<DeviceCoordinate>* pDXArray ) const = 0;
virtual DeviceCoordinate GetTextWidth() const { return FillDXArray( nullptr ); }
virtual void GetCaretPositions( int nArraySize, sal_Int32* pCaretXArray ) const = 0;
virtual bool IsKashidaPosValid ( int /*nCharPos*/ ) const { return true; } // i60594
// methods using glyph indexing
virtual bool GetNextGlyph(const GlyphItem** pGlyph, Point& rPos, int& nStart,
const LogicalFontInstance** ppGlyphFont = nullptr,
const vcl::font::PhysicalFontFace** pFallbackFont = nullptr) const = 0;
virtual bool GetOutline(basegfx::B2DPolyPolygonVector&) const;
bool GetBoundRect(tools::Rectangle&) const;
virtual SalLayoutGlyphs GetGlyphs() const;
protected:
// used by layout engines
SalLayout();
private:
SalLayout(const SalLayout&) = delete;
SalLayout& operator=(const SalLayout&) = delete;
protected:
int mnMinCharPos;
int mnEndCharPos;
int mnUnitsPerPixel;
Degree10 mnOrientation;
mutable Point maDrawOffset;
Point maDrawBase;
};
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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