view src/gui_dwrite.cpp @ 33471:baa62f464436 v9.0.1988

patch 9.0.1988: Vim9: potential use-after-free for class members Commit: https://github.com/vim/vim/commit/d2f4800099733216e28d59e1a5710f624b0d9ec1 Author: Yegappan Lakshmanan <yegappan@yahoo.com> Date: Thu Oct 5 20:24:18 2023 +0200 patch 9.0.1988: Vim9: potential use-after-free for class members Problem: Vim9: potential use-after-free for class members Solution: Use the class-related grow array for storing the member type instead of using a temporary type list grow array Use the type list grow array associated with the class than using a temporary type list grow array to allocate the class member type. For simple types, a predefined type is used. For complex types, the type is dynamically allocated from a grow array. For class variables, the type grow array in the class should be used. So that the lifetime of the type is same as the lifetime of the class. closes: #13279 Signed-off-by: Christian Brabandt <cb@256bit.org> Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
author Christian Brabandt <cb@256bit.org>
date Thu, 05 Oct 2023 20:30:11 +0200
parents faf7fcd1c8d5
children
line wrap: on
line source

/* vi:set ts=8 sts=4 sw=4 noet: */
/*
 * Author: MURAOKA Taro <koron.kaoriya@gmail.com>
 *
 * Contributors:
 *  - Ken Takata
 *  - Yasuhiro Matsumoto
 *
 * Copyright (C) 2013 MURAOKA Taro <koron.kaoriya@gmail.com>
 * THIS FILE IS DISTRIBUTED UNDER THE VIM LICENSE.
 */

#define WIN32_LEAN_AND_MEAN

#ifndef DYNAMIC_DIRECTX
# if WINVER < 0x0600
#  error WINVER must be 0x0600 or above to use DirectWrite(DirectX)
# endif
#endif

#include <windows.h>
#include <crtdbg.h>
#include <assert.h>
#include <math.h>
#include <d2d1.h>
#include <d2d1helper.h>

// Disable these macros to compile with old VC and newer SDK (V8.1 or later).
#if defined(_MSC_VER) && (_MSC_VER < 1700)
# define _COM_Outptr_ __out
# define _In_reads_(s)
# define _In_reads_opt_(s)
# define _Maybenull_
# define _Out_writes_(s)
# define _Out_writes_opt_(s)
# define _Out_writes_to_(x, y)
# define _Out_writes_to_opt_(x, y)
# define _Outptr_
#endif

#ifdef FEAT_DIRECTX_COLOR_EMOJI
# include <dwrite_2.h>
#else
# include <dwrite.h>
#endif

#include "gui_dwrite.h"

#ifdef __MINGW32__
# define __maybenull	SAL__maybenull
# define __in		SAL__in
# define __out		SAL__out
#endif

#ifdef __MINGW32__
# define UNUSED __attribute__((unused))
#else
# define UNUSED
#endif

#if (defined(_MSC_VER) && (_MSC_VER >= 1700)) || (__cplusplus >= 201103L)
# define FINAL final
#else
# define FINAL
#endif

#ifdef DYNAMIC_DIRECTX
extern "C" HINSTANCE vimLoadLib(const char *name);

typedef int (WINAPI *PGETUSERDEFAULTLOCALENAME)(LPWSTR, int);
typedef HRESULT (WINAPI *PD2D1CREATEFACTORY)(D2D1_FACTORY_TYPE,
	REFIID, const D2D1_FACTORY_OPTIONS *, void **);
typedef HRESULT (WINAPI *PDWRITECREATEFACTORY)(DWRITE_FACTORY_TYPE,
	REFIID, IUnknown **);

static HINSTANCE hD2D1DLL = NULL;
static HINSTANCE hDWriteDLL = NULL;

static PGETUSERDEFAULTLOCALENAME pGetUserDefaultLocaleName = NULL;
static PD2D1CREATEFACTORY pD2D1CreateFactory = NULL;
static PDWRITECREATEFACTORY pDWriteCreateFactory = NULL;

#define GetUserDefaultLocaleName	(*pGetUserDefaultLocaleName)
#define D2D1CreateFactory		(*pD2D1CreateFactory)
#define DWriteCreateFactory		(*pDWriteCreateFactory)

    static void
unload(HINSTANCE &hinst)
{
    if (hinst != NULL)
    {
	FreeLibrary(hinst);
	hinst = NULL;
    }
}
#endif // DYNAMIC_DIRECTX

template <class T> inline void SafeRelease(T **ppT)
{
    if (*ppT)
    {
	(*ppT)->Release();
	*ppT = NULL;
    }
}

    static DWRITE_PIXEL_GEOMETRY
ToPixelGeometry(int value)
{
    switch (value)
    {
	default:
	case 0:
	    return DWRITE_PIXEL_GEOMETRY_FLAT;
	case 1:
	    return DWRITE_PIXEL_GEOMETRY_RGB;
	case 2:
	    return DWRITE_PIXEL_GEOMETRY_BGR;
    }
}

    static int
ToInt(DWRITE_PIXEL_GEOMETRY value)
{
    switch (value)
    {
	case DWRITE_PIXEL_GEOMETRY_FLAT:
	    return 0;
	case DWRITE_PIXEL_GEOMETRY_RGB:
	    return 1;
	case DWRITE_PIXEL_GEOMETRY_BGR:
	    return 2;
	default:
	    return -1;
    }
}

    static DWRITE_RENDERING_MODE
ToRenderingMode(int value)
{
    switch (value)
    {
	default:
	case 0:
	    return DWRITE_RENDERING_MODE_DEFAULT;
	case 1:
	    return DWRITE_RENDERING_MODE_ALIASED;
	case 2:
	    return DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC;
	case 3:
	    return DWRITE_RENDERING_MODE_CLEARTYPE_GDI_NATURAL;
	case 4:
	    return DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL;
	case 5:
	    return DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
	case 6:
	    return DWRITE_RENDERING_MODE_OUTLINE;
    }
}

    static D2D1_TEXT_ANTIALIAS_MODE
ToTextAntialiasMode(int value)
{
    switch (value)
    {
	default:
	case 0:
	    return D2D1_TEXT_ANTIALIAS_MODE_DEFAULT;
	case 1:
	    return D2D1_TEXT_ANTIALIAS_MODE_CLEARTYPE;
	case 2:
	    return D2D1_TEXT_ANTIALIAS_MODE_GRAYSCALE;
	case 3:
	    return D2D1_TEXT_ANTIALIAS_MODE_ALIASED;
    }
}

    static int
ToInt(DWRITE_RENDERING_MODE value)
{
    switch (value)
    {
	case DWRITE_RENDERING_MODE_DEFAULT:
	    return 0;
	case DWRITE_RENDERING_MODE_ALIASED:
	    return 1;
	case DWRITE_RENDERING_MODE_CLEARTYPE_GDI_CLASSIC:
	    return 2;
	case DWRITE_RENDERING_MODE_CLEARTYPE_GDI_NATURAL:
	    return 3;
	case DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL:
	    return 4;
	case DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC:
	    return 5;
	case DWRITE_RENDERING_MODE_OUTLINE:
	    return 6;
	default:
	    return -1;
    }
}

class FontCache {
public:
    struct Item {
	HFONT              hFont;
	IDWriteTextFormat* pTextFormat;
	DWRITE_FONT_WEIGHT fontWeight;
	DWRITE_FONT_STYLE  fontStyle;
	Item() : hFont(NULL), pTextFormat(NULL) {}
    };

private:
    int mSize;
    Item *mItems;

public:
    FontCache(int size = 2) :
	mSize(size),
	mItems(new Item[size])
    {
    }

    ~FontCache()
    {
	for (int i = 0; i < mSize; ++i)
	    SafeRelease(&mItems[i].pTextFormat);
	delete[] mItems;
    }

    bool get(HFONT hFont, Item &item)
    {
	int n = find(hFont);
	if (n < 0)
	    return false;
	item = mItems[n];
	slide(n);
	return true;
    }

    void put(const Item& item)
    {
	int n = find(item.hFont);
	if (n < 0)
	    n = mSize - 1;
	if (mItems[n].pTextFormat != item.pTextFormat)
	{
	    SafeRelease(&mItems[n].pTextFormat);
	    if (item.pTextFormat != NULL)
		item.pTextFormat->AddRef();
	}
	mItems[n] = item;
	slide(n);
    }

private:
    int find(HFONT hFont)
    {
	for (int i = 0; i < mSize; ++i)
	{
	    if (mItems[i].hFont == hFont)
		return i;
	}
	return -1;
    }

    void slide(int nextTop)
    {
	if (nextTop == 0)
	    return;
	Item tmp = mItems[nextTop];
	for (int i = nextTop - 1; i >= 0; --i)
	    mItems[i + 1] = mItems[i];
	mItems[0] = tmp;
    }
};

enum DrawingMode {
    DM_GDI = 0,
    DM_DIRECTX = 1,
    DM_INTEROP = 2,
};

struct DWriteContext {
    HDC mHDC;
    RECT mBindRect;
    DrawingMode mDMode;
    HDC mInteropHDC;
    bool mDrawing;
    bool mFallbackDC;

    ID2D1Factory *mD2D1Factory;

    ID2D1DCRenderTarget *mRT;
    ID2D1GdiInteropRenderTarget *mGDIRT;
    ID2D1SolidColorBrush *mBrush;
    ID2D1Bitmap *mBitmap;

    IDWriteFactory *mDWriteFactory;
#ifdef FEAT_DIRECTX_COLOR_EMOJI
    IDWriteFactory2 *mDWriteFactory2;
#endif

    IDWriteGdiInterop *mGdiInterop;
    IDWriteRenderingParams *mRenderingParams;

    FontCache mFontCache;
    IDWriteTextFormat *mTextFormat;
    DWRITE_FONT_WEIGHT mFontWeight;
    DWRITE_FONT_STYLE mFontStyle;

    D2D1_TEXT_ANTIALIAS_MODE mTextAntialiasMode;

    // METHODS

    DWriteContext();

    virtual ~DWriteContext();

    HRESULT CreateDeviceResources();

    void DiscardDeviceResources();

    HRESULT CreateTextFormatFromLOGFONT(const LOGFONTW &logFont,
	    IDWriteTextFormat **ppTextFormat);

    HRESULT SetFontByLOGFONT(const LOGFONTW &logFont);

    void SetFont(HFONT hFont);

    void Rebind();

    void BindDC(HDC hdc, const RECT *rect);

    HRESULT SetDrawingMode(DrawingMode mode);

    ID2D1Brush* SolidBrush(COLORREF color);

    void DrawText(const WCHAR *text, int len,
	int x, int y, int w, int h, int cellWidth, COLORREF color,
	UINT fuOptions, const RECT *lprc, const INT *lpDx);

    void FillRect(const RECT *rc, COLORREF color);

    void DrawLine(int x1, int y1, int x2, int y2, COLORREF color);

    void SetPixel(int x, int y, COLORREF color);

    void Scroll(int x, int y, const RECT *rc);

    void Flush();

    void SetRenderingParams(
	    const DWriteRenderingParams *params);

    DWriteRenderingParams *GetRenderingParams(
	    DWriteRenderingParams *params);
};

class AdjustedGlyphRun : public DWRITE_GLYPH_RUN
{
private:
    FLOAT &mAccum;
    FLOAT mDelta;
    FLOAT *mAdjustedAdvances;

public:
    AdjustedGlyphRun(
	    const DWRITE_GLYPH_RUN *glyphRun,
	    FLOAT cellWidth,
	    FLOAT &accum) :
	DWRITE_GLYPH_RUN(*glyphRun),
	mAccum(accum),
	mDelta(0.0f),
	mAdjustedAdvances(new FLOAT[glyphRun->glyphCount])
    {
	assert(cellWidth != 0.0f);
	for (UINT32 i = 0; i < glyphRun->glyphCount; ++i)
	{
	    FLOAT orig = glyphRun->glyphAdvances[i];
	    FLOAT adjusted = adjustToCell(orig, cellWidth);
	    mAdjustedAdvances[i] = adjusted;
	    mDelta += adjusted - orig;
	}
	glyphAdvances = mAdjustedAdvances;
    }

    ~AdjustedGlyphRun()
    {
	mAccum += mDelta;
	delete[] mAdjustedAdvances;
    }

    static FLOAT adjustToCell(FLOAT value, FLOAT cellWidth)
    {
	int cellCount = int(floor(value / cellWidth + 0.5f));
	if (cellCount < 1)
	    cellCount = 1;
	return cellCount * cellWidth;
    }
};

struct TextRendererContext {
    // const fields.
    COLORREF color;
    FLOAT cellWidth;

    // working fields.
    FLOAT offsetX;
};

class TextRenderer FINAL : public IDWriteTextRenderer
{
public:
    TextRenderer(
	    DWriteContext* pDWC) :
	cRefCount_(0),
	pDWC_(pDWC)
    {
	AddRef();
    }

    // add "virtual" to avoid a compiler warning
    virtual ~TextRenderer()
    {
    }

    IFACEMETHOD(IsPixelSnappingDisabled)(
	__maybenull void* clientDrawingContext UNUSED,
	__out BOOL* isDisabled)
    {
	*isDisabled = FALSE;
	return S_OK;
    }

    IFACEMETHOD(GetCurrentTransform)(
	__maybenull void* clientDrawingContext UNUSED,
	__out DWRITE_MATRIX* transform)
    {
	// forward the render target's transform
	pDWC_->mRT->GetTransform(
		reinterpret_cast<D2D1_MATRIX_3X2_F*>(transform));
	return S_OK;
    }

    IFACEMETHOD(GetPixelsPerDip)(
	__maybenull void* clientDrawingContext UNUSED,
	__out FLOAT* pixelsPerDip)
    {
	float dpiX, unused;
	pDWC_->mRT->GetDpi(&dpiX, &unused);
	*pixelsPerDip = dpiX / 96.0f;
	return S_OK;
    }

    IFACEMETHOD(DrawUnderline)(
	__maybenull void* clientDrawingContext UNUSED,
	FLOAT baselineOriginX UNUSED,
	FLOAT baselineOriginY UNUSED,
	__in DWRITE_UNDERLINE const* underline UNUSED,
	IUnknown* clientDrawingEffect UNUSED)
    {
	return E_NOTIMPL;
    }

    IFACEMETHOD(DrawStrikethrough)(
	__maybenull void* clientDrawingContext UNUSED,
	FLOAT baselineOriginX UNUSED,
	FLOAT baselineOriginY UNUSED,
	__in DWRITE_STRIKETHROUGH const* strikethrough UNUSED,
	IUnknown* clientDrawingEffect UNUSED)
    {
	return E_NOTIMPL;
    }

    IFACEMETHOD(DrawInlineObject)(
	__maybenull void* clientDrawingContext UNUSED,
	FLOAT originX UNUSED,
	FLOAT originY UNUSED,
	IDWriteInlineObject* inlineObject UNUSED,
	BOOL isSideways UNUSED,
	BOOL isRightToLeft UNUSED,
	IUnknown* clientDrawingEffect UNUSED)
    {
	return E_NOTIMPL;
    }

    IFACEMETHOD(DrawGlyphRun)(
	__maybenull void* clientDrawingContext,
	FLOAT baselineOriginX,
	FLOAT baselineOriginY,
	DWRITE_MEASURING_MODE measuringMode UNUSED,
	__in DWRITE_GLYPH_RUN const* glyphRun,
	__in DWRITE_GLYPH_RUN_DESCRIPTION const* glyphRunDescription UNUSED,
	IUnknown* clientDrawingEffect UNUSED)
    {
	TextRendererContext *context =
	    reinterpret_cast<TextRendererContext*>(clientDrawingContext);

	AdjustedGlyphRun adjustedGlyphRun(glyphRun, context->cellWidth,
		context->offsetX);

#ifdef FEAT_DIRECTX_COLOR_EMOJI
	if (pDWC_->mDWriteFactory2 != NULL)
	{
	    IDWriteColorGlyphRunEnumerator *enumerator = NULL;
	    HRESULT hr = pDWC_->mDWriteFactory2->TranslateColorGlyphRun(
		baselineOriginX + context->offsetX,
		baselineOriginY,
		&adjustedGlyphRun,
		NULL,
		DWRITE_MEASURING_MODE_GDI_NATURAL,
		NULL,
		0,
		&enumerator);
	    if (SUCCEEDED(hr))
	    {
		// Draw by IDWriteFactory2 for color emoji
		BOOL hasRun = TRUE;
		enumerator->MoveNext(&hasRun);
		while (hasRun)
		{
		    const DWRITE_COLOR_GLYPH_RUN* colorGlyphRun;
		    enumerator->GetCurrentRun(&colorGlyphRun);

		    pDWC_->mBrush->SetColor(colorGlyphRun->runColor);
		    pDWC_->mRT->DrawGlyphRun(
			    D2D1::Point2F(
				colorGlyphRun->baselineOriginX,
				colorGlyphRun->baselineOriginY),
			    &colorGlyphRun->glyphRun,
			    pDWC_->mBrush,
			    DWRITE_MEASURING_MODE_NATURAL);
		    enumerator->MoveNext(&hasRun);
		}
		SafeRelease(&enumerator);
		return S_OK;
	    }
	}
#endif

	// Draw by IDWriteFactory (without color emoji)
	pDWC_->mRT->DrawGlyphRun(
		D2D1::Point2F(
		    baselineOriginX + context->offsetX,
		    baselineOriginY),
		&adjustedGlyphRun,
		pDWC_->SolidBrush(context->color),
		DWRITE_MEASURING_MODE_NATURAL);
	return S_OK;
    }

public:
    IFACEMETHOD_(unsigned long, AddRef) ()
    {
	return InterlockedIncrement(&cRefCount_);
    }

    IFACEMETHOD_(unsigned long, Release) ()
    {
	long newCount = InterlockedDecrement(&cRefCount_);

	if (newCount == 0)
	{
	    delete this;
	    return 0;
	}
	return newCount;
    }

    IFACEMETHOD(QueryInterface)(
	IID const& riid,
	void** ppvObject)
    {
	if (__uuidof(IDWriteTextRenderer) == riid)
	{
	    *ppvObject = this;
	}
	else if (__uuidof(IDWritePixelSnapping) == riid)
	{
	    *ppvObject = this;
	}
	else if (__uuidof(IUnknown) == riid)
	{
	    *ppvObject = this;
	}
	else
	{
	    *ppvObject = NULL;
	    return E_FAIL;
	}

	return S_OK;
    }

private:
    long cRefCount_;
    DWriteContext* pDWC_;
};

DWriteContext::DWriteContext() :
    mHDC(NULL),
    mBindRect(),
    mDMode(DM_GDI),
    mInteropHDC(NULL),
    mDrawing(false),
    mFallbackDC(false),
    mD2D1Factory(NULL),
    mRT(NULL),
    mGDIRT(NULL),
    mBrush(NULL),
    mBitmap(NULL),
    mDWriteFactory(NULL),
#ifdef FEAT_DIRECTX_COLOR_EMOJI
    mDWriteFactory2(NULL),
#endif
    mGdiInterop(NULL),
    mRenderingParams(NULL),
    mFontCache(8),
    mTextFormat(NULL),
    mFontWeight(DWRITE_FONT_WEIGHT_NORMAL),
    mFontStyle(DWRITE_FONT_STYLE_NORMAL),
    mTextAntialiasMode(D2D1_TEXT_ANTIALIAS_MODE_DEFAULT)
{
    HRESULT hr;

    hr = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,
	    __uuidof(ID2D1Factory), NULL,
	    reinterpret_cast<void**>(&mD2D1Factory));
    _RPT2(_CRT_WARN, "D2D1CreateFactory: hr=%p p=%p\n", hr, mD2D1Factory);

    if (SUCCEEDED(hr))
    {
	hr = DWriteCreateFactory(
		DWRITE_FACTORY_TYPE_SHARED,
		__uuidof(IDWriteFactory),
		reinterpret_cast<IUnknown**>(&mDWriteFactory));
	_RPT2(_CRT_WARN, "DWriteCreateFactory: hr=%p p=%p\n", hr,
		mDWriteFactory);
    }

#ifdef FEAT_DIRECTX_COLOR_EMOJI
    if (SUCCEEDED(hr))
    {
	DWriteCreateFactory(
		DWRITE_FACTORY_TYPE_SHARED,
		__uuidof(IDWriteFactory2),
		reinterpret_cast<IUnknown**>(&mDWriteFactory2));
	_RPT1(_CRT_WARN, "IDWriteFactory2: %s\n", SUCCEEDED(hr) ? "available" : "not available");
    }
#endif

    if (SUCCEEDED(hr))
    {
	hr = mDWriteFactory->GetGdiInterop(&mGdiInterop);
	_RPT2(_CRT_WARN, "GetGdiInterop: hr=%p p=%p\n", hr, mGdiInterop);
    }

    if (SUCCEEDED(hr))
    {
	hr = mDWriteFactory->CreateRenderingParams(&mRenderingParams);
	_RPT2(_CRT_WARN, "CreateRenderingParams: hr=%p p=%p\n", hr,
		mRenderingParams);
    }
}

DWriteContext::~DWriteContext()
{
    SafeRelease(&mTextFormat);
    SafeRelease(&mRenderingParams);
    SafeRelease(&mGdiInterop);
    SafeRelease(&mDWriteFactory);
#ifdef FEAT_DIRECTX_COLOR_EMOJI
    SafeRelease(&mDWriteFactory2);
#endif
    SafeRelease(&mBitmap);
    SafeRelease(&mBrush);
    SafeRelease(&mGDIRT);
    SafeRelease(&mRT);
    SafeRelease(&mD2D1Factory);
}

    HRESULT
DWriteContext::CreateDeviceResources()
{
    HRESULT hr;

    if (mRT != NULL)
	return S_OK;

    D2D1_RENDER_TARGET_PROPERTIES props = {
	D2D1_RENDER_TARGET_TYPE_DEFAULT,
	{ DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_IGNORE },
	0, 0,
	D2D1_RENDER_TARGET_USAGE_GDI_COMPATIBLE,
	D2D1_FEATURE_LEVEL_DEFAULT
    };
    hr = mD2D1Factory->CreateDCRenderTarget(&props, &mRT);
    _RPT2(_CRT_WARN, "CreateDCRenderTarget: hr=%p p=%p\n", hr, mRT);

    if (SUCCEEDED(hr))
    {
	// This always succeeds.
	mRT->QueryInterface(
		__uuidof(ID2D1GdiInteropRenderTarget),
		reinterpret_cast<void**>(&mGDIRT));
	_RPT1(_CRT_WARN, "GdiInteropRenderTarget: p=%p\n", mGDIRT);
    }

    if (SUCCEEDED(hr))
    {
	hr = mRT->CreateSolidColorBrush(
		D2D1::ColorF(D2D1::ColorF::Black),
		&mBrush);
	_RPT2(_CRT_WARN, "CreateSolidColorBrush: hr=%p p=%p\n", hr, mBrush);
    }

    if (SUCCEEDED(hr))
	Rebind();

    return hr;
}

    void
DWriteContext::DiscardDeviceResources()
{
    SafeRelease(&mBitmap);
    SafeRelease(&mBrush);
    SafeRelease(&mGDIRT);
    SafeRelease(&mRT);
}

    HRESULT
DWriteContext::CreateTextFormatFromLOGFONT(const LOGFONTW &logFont,
	IDWriteTextFormat **ppTextFormat)
{
    // Most of this function is copied from: https://github.com/Microsoft/Windows-classic-samples/blob/master/Samples/Win7Samples/multimedia/DirectWrite/RenderTest/TextHelpers.cpp
    HRESULT hr = S_OK;
    IDWriteTextFormat *pTextFormat = NULL;

    IDWriteFont *font = NULL;
    IDWriteFontFamily *fontFamily = NULL;
    IDWriteLocalizedStrings *localizedFamilyNames = NULL;
    float fontSize = 0;

    if (SUCCEEDED(hr))
    {
	hr = mGdiInterop->CreateFontFromLOGFONT(&logFont, &font);
    }

    // Get the font family to which this font belongs.
    if (SUCCEEDED(hr))
    {
	hr = font->GetFontFamily(&fontFamily);
    }

    // Get the family names. This returns an object that encapsulates one or
    // more names with the same meaning but in different languages.
    if (SUCCEEDED(hr))
    {
	hr = fontFamily->GetFamilyNames(&localizedFamilyNames);
    }

    // Get the family name at index zero. If we were going to display the name
    // we'd want to try to find one that matched the use locale, but for
    // purposes of creating a text format object any language will do.

    wchar_t familyName[100];
    if (SUCCEEDED(hr))
    {
	hr = localizedFamilyNames->GetString(0, familyName,
		ARRAYSIZE(familyName));
    }

    if (SUCCEEDED(hr))
    {
	// Use lfHeight of the LOGFONT as font size.
	fontSize = float(logFont.lfHeight);

	if (fontSize < 0)
	{
	    // Negative lfHeight represents the size of the em unit.
	    fontSize = -fontSize;
	}
	else
	{
	    // Positive lfHeight represents the cell height (ascent +
	    // descent).
	    DWRITE_FONT_METRICS fontMetrics;
	    font->GetMetrics(&fontMetrics);

	    // Convert the cell height (ascent + descent) from design units
	    // to ems.
	    float cellHeight = static_cast<float>(
		    fontMetrics.ascent + fontMetrics.descent)
		/ fontMetrics.designUnitsPerEm;

	    // Divide the font size by the cell height to get the font em
	    // size.
	    fontSize /= cellHeight;
	}
    }

    // The text format includes a locale name. Ideally, this would be the
    // language of the text, which may or may not be the same as the primary
    // language of the user. However, for our purposes the user locale will do.
    wchar_t localeName[LOCALE_NAME_MAX_LENGTH];
    if (SUCCEEDED(hr))
    {
	if (GetUserDefaultLocaleName(localeName, LOCALE_NAME_MAX_LENGTH) == 0)
	    hr = HRESULT_FROM_WIN32(GetLastError());
    }

    if (SUCCEEDED(hr))
    {
	// Create the text format object.
	hr = mDWriteFactory->CreateTextFormat(
		familyName,
		NULL, // no custom font collection
		font->GetWeight(),
		font->GetStyle(),
		font->GetStretch(),
		fontSize,
		localeName,
		&pTextFormat);
    }

    if (SUCCEEDED(hr))
	hr = pTextFormat->SetTextAlignment(DWRITE_TEXT_ALIGNMENT_LEADING);

    if (SUCCEEDED(hr))
	hr = pTextFormat->SetParagraphAlignment(
		DWRITE_PARAGRAPH_ALIGNMENT_FAR);

    if (SUCCEEDED(hr))
	hr = pTextFormat->SetWordWrapping(DWRITE_WORD_WRAPPING_NO_WRAP);

    SafeRelease(&localizedFamilyNames);
    SafeRelease(&fontFamily);
    SafeRelease(&font);

    if (SUCCEEDED(hr))
	*ppTextFormat = pTextFormat;
    else
	SafeRelease(&pTextFormat);

    return hr;
}

    HRESULT
DWriteContext::SetFontByLOGFONT(const LOGFONTW &logFont)
{
    HRESULT hr = S_OK;
    IDWriteTextFormat *pTextFormat = NULL;

    hr = CreateTextFormatFromLOGFONT(logFont, &pTextFormat);

    if (SUCCEEDED(hr))
    {
	SafeRelease(&mTextFormat);
	mTextFormat = pTextFormat;
	mFontWeight = static_cast<DWRITE_FONT_WEIGHT>(logFont.lfWeight);
	mFontStyle = logFont.lfItalic ? DWRITE_FONT_STYLE_ITALIC
	    : DWRITE_FONT_STYLE_NORMAL;
    }

    return hr;
}

    void
DWriteContext::SetFont(HFONT hFont)
{
    FontCache::Item item;
    if (mFontCache.get(hFont, item))
    {
	if (item.pTextFormat != NULL)
	{
	    item.pTextFormat->AddRef();
	    SafeRelease(&mTextFormat);
	    mTextFormat = item.pTextFormat;
	    mFontWeight = item.fontWeight;
	    mFontStyle = item.fontStyle;
	    mFallbackDC = false;
	}
	else
	    mFallbackDC = true;
	return;
    }

    HRESULT hr = E_FAIL;
    LOGFONTW lf;
    if (GetObjectW(hFont, sizeof(lf), &lf))
	hr = SetFontByLOGFONT(lf);

    item.hFont = hFont;
    if (SUCCEEDED(hr))
    {
	item.pTextFormat = mTextFormat;
	item.fontWeight = mFontWeight;
	item.fontStyle = mFontStyle;
	mFallbackDC = false;
    }
    else
	mFallbackDC = true;
    mFontCache.put(item);
}

    void
DWriteContext::Rebind()
{
    SafeRelease(&mBitmap);

    mRT->BindDC(mHDC, &mBindRect);
    mRT->SetTransform(D2D1::IdentityMatrix());

    D2D1_BITMAP_PROPERTIES props = {
	{DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_IGNORE},
	96.0f, 96.0f
    };
    mRT->CreateBitmap(
	    D2D1::SizeU(mBindRect.right - mBindRect.left,
		mBindRect.bottom - mBindRect.top),
	    props, &mBitmap);
}

    void
DWriteContext::BindDC(HDC hdc, const RECT *rect)
{
    mHDC = hdc;
    mBindRect = *rect;

    if (mRT == NULL)
	CreateDeviceResources();
    else
    {
	Flush();
	Rebind();
    }
}

extern "C" void redraw_later_clear(void);

    HRESULT
DWriteContext::SetDrawingMode(DrawingMode mode)
{
    HRESULT hr = S_OK;

    switch (mode)
    {
	default:
	case DM_GDI:
	    if (mInteropHDC != NULL)
	    {
		mGDIRT->ReleaseDC(NULL);
		mInteropHDC = NULL;
	    }
	    if (mDrawing)
	    {
		hr = mRT->EndDraw();
		if (hr == (HRESULT)D2DERR_RECREATE_TARGET)
		{
		    hr = S_OK;
		    DiscardDeviceResources();
		    CreateDeviceResources();
		    redraw_later_clear();
		}
		mDrawing = false;
	    }
	    break;

	case DM_DIRECTX:
	    if (mInteropHDC != NULL)
	    {
		mGDIRT->ReleaseDC(NULL);
		mInteropHDC = NULL;
	    }
	    else if (mDrawing == false)
	    {
		CreateDeviceResources();
		mRT->BeginDraw();
		mDrawing = true;
	    }
	    break;

	case DM_INTEROP:
	    if (mDrawing == false)
	    {
		CreateDeviceResources();
		mRT->BeginDraw();
		mDrawing = true;
	    }
	    if (mInteropHDC == NULL)
		hr = mGDIRT->GetDC(D2D1_DC_INITIALIZE_MODE_COPY, &mInteropHDC);
	    break;
    }
    mDMode = mode;
    return hr;
}

    ID2D1Brush*
DWriteContext::SolidBrush(COLORREF color)
{
    mBrush->SetColor(D2D1::ColorF(UINT32(GetRValue(color)) << 16 |
		UINT32(GetGValue(color)) << 8 | UINT32(GetBValue(color))));
    return mBrush;
}

    void
DWriteContext::DrawText(const WCHAR *text, int len,
	int x, int y, int w, int h, int cellWidth, COLORREF color,
	UINT fuOptions, const RECT *lprc, const INT *lpDx)
{
    if (mFallbackDC)
    {
	// Fall back to GDI rendering.
	HRESULT hr = SetDrawingMode(DM_INTEROP);
	if (SUCCEEDED(hr))
	{
	    HGDIOBJ hFont = ::GetCurrentObject(mHDC, OBJ_FONT);
	    HGDIOBJ hOldFont = ::SelectObject(mInteropHDC, hFont);
	    ::SetTextColor(mInteropHDC, color);
	    ::SetBkMode(mInteropHDC, ::GetBkMode(mHDC));
	    ::ExtTextOutW(mInteropHDC, x, y, fuOptions, lprc, text, len, lpDx);
	    ::SelectObject(mInteropHDC, hOldFont);
	}
	return;
    }

    HRESULT hr;
    IDWriteTextLayout *textLayout = NULL;

    SetDrawingMode(DM_DIRECTX);

    hr = mDWriteFactory->CreateTextLayout(text, len, mTextFormat,
	    FLOAT(w), FLOAT(h), &textLayout);

    if (SUCCEEDED(hr))
    {
	DWRITE_TEXT_RANGE textRange = { 0, UINT32(len) };
	textLayout->SetFontWeight(mFontWeight, textRange);
	textLayout->SetFontStyle(mFontStyle, textRange);

	TextRenderer renderer(this);
	TextRendererContext context = { color, FLOAT(cellWidth), 0.0f };
	textLayout->Draw(&context, &renderer, FLOAT(x), FLOAT(y));
    }

    SafeRelease(&textLayout);
}

    void
DWriteContext::FillRect(const RECT *rc, COLORREF color)
{
    if (mDMode == DM_INTEROP)
    {
	// GDI functions are used before this call.  Keep using GDI.
	// (Switching to Direct2D causes terrible slowdown.)
	HBRUSH hbr = ::CreateSolidBrush(color);
	::FillRect(mInteropHDC, rc, hbr);
	::DeleteObject(HGDIOBJ(hbr));
    }
    else
    {
	SetDrawingMode(DM_DIRECTX);
	mRT->FillRectangle(
		D2D1::RectF(FLOAT(rc->left), FLOAT(rc->top),
		    FLOAT(rc->right), FLOAT(rc->bottom)),
		SolidBrush(color));
    }
}

    void
DWriteContext::DrawLine(int x1, int y1, int x2, int y2, COLORREF color)
{
    if (mDMode == DM_INTEROP)
    {
	// GDI functions are used before this call.  Keep using GDI.
	// (Switching to Direct2D causes terrible slowdown.)
	HPEN hpen = ::CreatePen(PS_SOLID, 1, color);
	HGDIOBJ old_pen = ::SelectObject(mInteropHDC, HGDIOBJ(hpen));
	::MoveToEx(mInteropHDC, x1, y1, NULL);
	::LineTo(mInteropHDC, x2, y2);
	::SelectObject(mInteropHDC, old_pen);
	::DeleteObject(HGDIOBJ(hpen));
    }
    else
    {
	SetDrawingMode(DM_DIRECTX);
	mRT->DrawLine(
		D2D1::Point2F(FLOAT(x1), FLOAT(y1) + 0.5f),
		D2D1::Point2F(FLOAT(x2), FLOAT(y2) + 0.5f),
		SolidBrush(color));
    }
}

    void
DWriteContext::SetPixel(int x, int y, COLORREF color)
{
    if (mDMode == DM_INTEROP)
    {
	// GDI functions are used before this call.  Keep using GDI.
	// (Switching to Direct2D causes terrible slowdown.)
	::SetPixel(mInteropHDC, x, y, color);
    }
    else
    {
	SetDrawingMode(DM_DIRECTX);
	// Direct2D doesn't have SetPixel API.  Use DrawLine instead.
	mRT->DrawLine(
		D2D1::Point2F(FLOAT(x), FLOAT(y) + 0.5f),
		D2D1::Point2F(FLOAT(x+1), FLOAT(y) + 0.5f),
		SolidBrush(color));
    }
}

    void
DWriteContext::Scroll(int x, int y, const RECT *rc)
{
    SetDrawingMode(DM_DIRECTX);
    mRT->Flush();

    D2D1_RECT_U srcRect;
    D2D1_POINT_2U destPoint;
    if (x >= 0)
    {
	srcRect.left = rc->left;
	srcRect.right = rc->right - x;
	destPoint.x = rc->left + x;
    }
    else
    {
	srcRect.left = rc->left - x;
	srcRect.right = rc->right;
	destPoint.x = rc->left;
    }
    if (y >= 0)
    {
	srcRect.top = rc->top;
	srcRect.bottom = rc->bottom - y;
	destPoint.y = rc->top + y;
    }
    else
    {
	srcRect.top = rc->top - y;
	srcRect.bottom = rc->bottom;
	destPoint.y = rc->top;
    }
    mBitmap->CopyFromRenderTarget(&destPoint, mRT, &srcRect);

    D2D1_RECT_F destRect = {
	    FLOAT(destPoint.x), FLOAT(destPoint.y),
	    FLOAT(destPoint.x + srcRect.right - srcRect.left),
	    FLOAT(destPoint.y + srcRect.bottom - srcRect.top)
    };
    mRT->DrawBitmap(mBitmap, destRect, 1.0F,
	    D2D1_BITMAP_INTERPOLATION_MODE_NEAREST_NEIGHBOR, destRect);
}

    void
DWriteContext::Flush()
{
    SetDrawingMode(DM_GDI);
}

    void
DWriteContext::SetRenderingParams(
	const DWriteRenderingParams *params)
{
    if (mDWriteFactory == NULL)
	return;

    IDWriteRenderingParams *renderingParams = NULL;
    D2D1_TEXT_ANTIALIAS_MODE textAntialiasMode =
	D2D1_TEXT_ANTIALIAS_MODE_DEFAULT;
    HRESULT hr;
    if (params != NULL)
    {
	hr = mDWriteFactory->CreateCustomRenderingParams(params->gamma,
		params->enhancedContrast, params->clearTypeLevel,
		ToPixelGeometry(params->pixelGeometry),
		ToRenderingMode(params->renderingMode), &renderingParams);
	textAntialiasMode = ToTextAntialiasMode(params->textAntialiasMode);
    }
    else
	hr = mDWriteFactory->CreateRenderingParams(&renderingParams);
    if (SUCCEEDED(hr) && renderingParams != NULL)
    {
	SafeRelease(&mRenderingParams);
	mRenderingParams = renderingParams;
	mTextAntialiasMode = textAntialiasMode;

	Flush();
	mRT->SetTextRenderingParams(mRenderingParams);
	mRT->SetTextAntialiasMode(mTextAntialiasMode);
    }
}

    DWriteRenderingParams *
DWriteContext::GetRenderingParams(
	DWriteRenderingParams *params)
{
    if (params != NULL && mRenderingParams != NULL)
    {
	params->gamma = mRenderingParams->GetGamma();
	params->enhancedContrast = mRenderingParams->GetEnhancedContrast();
	params->clearTypeLevel = mRenderingParams->GetClearTypeLevel();
	params->pixelGeometry = ToInt(mRenderingParams->GetPixelGeometry());
	params->renderingMode = ToInt(mRenderingParams->GetRenderingMode());
	params->textAntialiasMode = mTextAntialiasMode;
    }
    return params;
}

////////////////////////////////////////////////////////////////////////////
// PUBLIC C INTERFACES

    void
DWrite_Init(void)
{
#ifdef DYNAMIC_DIRECTX
    // Load libraries.
    hD2D1DLL = vimLoadLib("d2d1.dll");
    hDWriteDLL = vimLoadLib("dwrite.dll");
    if (hD2D1DLL == NULL || hDWriteDLL == NULL)
    {
	DWrite_Final();
	return;
    }
    // Get address of procedures.
    pGetUserDefaultLocaleName = (PGETUSERDEFAULTLOCALENAME)GetProcAddress(
	    GetModuleHandle("kernel32.dll"), "GetUserDefaultLocaleName");
    pD2D1CreateFactory = (PD2D1CREATEFACTORY)GetProcAddress(hD2D1DLL,
	    "D2D1CreateFactory");
    pDWriteCreateFactory = (PDWRITECREATEFACTORY)GetProcAddress(hDWriteDLL,
	    "DWriteCreateFactory");
#endif
}

    void
DWrite_Final(void)
{
#ifdef DYNAMIC_DIRECTX
    pGetUserDefaultLocaleName = NULL;
    pD2D1CreateFactory = NULL;
    pDWriteCreateFactory = NULL;
    unload(hDWriteDLL);
    unload(hD2D1DLL);
#endif
}

    DWriteContext *
DWriteContext_Open(void)
{
#ifdef DYNAMIC_DIRECTX
    if (pGetUserDefaultLocaleName == NULL || pD2D1CreateFactory == NULL
	    || pDWriteCreateFactory == NULL)
	return NULL;
#endif
    return new DWriteContext();
}

    void
DWriteContext_BindDC(DWriteContext *ctx, HDC hdc, const RECT *rect)
{
    if (ctx != NULL)
	ctx->BindDC(hdc, rect);
}

    void
DWriteContext_SetFont(DWriteContext *ctx, HFONT hFont)
{
    if (ctx != NULL)
	ctx->SetFont(hFont);
}

    void
DWriteContext_DrawText(
	DWriteContext *ctx,
	const WCHAR *text,
	int len,
	int x,
	int y,
	int w,
	int h,
	int cellWidth,
	COLORREF color,
	UINT fuOptions,
	const RECT *lprc,
	const INT *lpDx)
{
    if (ctx != NULL)
	ctx->DrawText(text, len, x, y, w, h, cellWidth, color,
		fuOptions, lprc, lpDx);
}

    void
DWriteContext_FillRect(DWriteContext *ctx, const RECT *rc, COLORREF color)
{
    if (ctx != NULL)
	ctx->FillRect(rc, color);
}

    void
DWriteContext_DrawLine(DWriteContext *ctx, int x1, int y1, int x2, int y2,
	COLORREF color)
{
    if (ctx != NULL)
	ctx->DrawLine(x1, y1, x2, y2, color);
}

    void
DWriteContext_SetPixel(DWriteContext *ctx, int x, int y, COLORREF color)
{
    if (ctx != NULL)
	ctx->SetPixel(x, y, color);
}

    void
DWriteContext_Scroll(DWriteContext *ctx, int x, int y, const RECT *rc)
{
    if (ctx != NULL)
	ctx->Scroll(x, y, rc);
}

    void
DWriteContext_Flush(DWriteContext *ctx)
{
    if (ctx != NULL)
	ctx->Flush();
}

    void
DWriteContext_Close(DWriteContext *ctx)
{
    delete ctx;
}

    void
DWriteContext_SetRenderingParams(
	DWriteContext *ctx,
	const DWriteRenderingParams *params)
{
    if (ctx != NULL)
	ctx->SetRenderingParams(params);
}

    DWriteRenderingParams *
DWriteContext_GetRenderingParams(
	DWriteContext *ctx,
	DWriteRenderingParams *params)
{
    if (ctx != NULL)
	return ctx->GetRenderingParams(params);
    else
	return NULL;
}