dlls/gdiplus/gdiplus.c - wine - Git at Google

 /*
  * Copyright (C) 2007 Google (Evan Stade)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */

 #include <stdarg.h>
 #include <math.h>

 #include "windef.h"
 #include "winbase.h"
 #include "winerror.h"
 #include "wine/debug.h"
 #include "wingdi.h"

 #include "objbase.h"

 #include "winreg.h"
 #include "shlwapi.h"

 #include "gdiplus.h"
 #include "gdiplus_private.h"

 WINE_DEFAULT_DEBUG_CHANNEL(gdiplus);

 static Status WINAPI NotificationHook(ULONG_PTR *token)
 {
     TRACE("%p\n", token);
     if(!token)
         return InvalidParameter;

     return Ok;
 }

 static void WINAPI NotificationUnhook(ULONG_PTR token)
 {
     TRACE("%ld\n", token);
 }

 /*****************************************************
  *      DllMain
  */
 BOOL WINAPI DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved)
 {
     TRACE("(%p, %d, %p)\n", hinst, reason, reserved);

     switch(reason)
     {
     case DLL_WINE_PREATTACH:
         return FALSE;  /* prefer native version */

     case DLL_PROCESS_ATTACH:
         DisableThreadLibraryCalls( hinst );
         break;

     case DLL_PROCESS_DETACH:
         free_installed_fonts();
         break;
     }
     return TRUE;
 }

 /*****************************************************
  *      GdiplusStartup [GDIPLUS.@]
  */
 Status WINAPI GdiplusStartup(ULONG_PTR *token, const struct GdiplusStartupInput *input,
                              struct GdiplusStartupOutput *output)
 {
     if(!token || !input)
         return InvalidParameter;

     TRACE("%p %p %p\n", token, input, output);
     TRACE("GdiplusStartupInput %d %p %d %d\n", input->GdiplusVersion,
           input->DebugEventCallback, input->SuppressBackgroundThread,
           input->SuppressExternalCodecs);

     if(input->GdiplusVersion < 1 || input->GdiplusVersion > 2)
         return UnsupportedGdiplusVersion;

     if(input->SuppressBackgroundThread){
         if(!output)
             return InvalidParameter;

         output->NotificationHook = NotificationHook;
         output->NotificationUnhook = NotificationUnhook;
     }

     *token = 0xdeadbeef;

     /* FIXME: DebugEventCallback ignored */

     return Ok;
 }

 GpStatus WINAPI GdiplusNotificationHook(ULONG_PTR *token)
 {
     FIXME("%p\n", token);
     return NotificationHook(token);
 }

 void WINAPI GdiplusNotificationUnhook(ULONG_PTR token)
 {
     FIXME("%ld\n", token);
     NotificationUnhook(token);
 }

 /*****************************************************
  *      GdiplusShutdown [GDIPLUS.@]
  */
 void WINAPI GdiplusShutdown(ULONG_PTR token)
 {
     /* FIXME: no object tracking */
 }

 /*****************************************************
  *      GdipAlloc [GDIPLUS.@]
  */
 void* WINGDIPAPI GdipAlloc(SIZE_T size)
 {
     return HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, size);
 }

 /*****************************************************
  *      GdipFree [GDIPLUS.@]
  */
 void WINGDIPAPI GdipFree(void* ptr)
 {
     HeapFree(GetProcessHeap(), 0, ptr);
 }

 /* Calculates the bezier points needed to fill in the arc portion starting at
  * angle start and ending at end.  These two angles should be no more than 90
  * degrees from each other.  x1, y1, x2, y2 describes the bounding box (upper
  * left and width and height).  Angles must be in radians. write_first indicates
  * that the first bezier point should be written out (usually this is false).
  * pt is the array of GpPointFs that gets written to.
  **/
 static void add_arc_part(GpPointF * pt, REAL x1, REAL y1, REAL x2, REAL y2,
     REAL start, REAL end, BOOL write_first)
 {
     REAL center_x, center_y, rad_x, rad_y, cos_start, cos_end,
         sin_start, sin_end, a, half;
     INT i;

     rad_x = x2 / 2.0;
     rad_y = y2 / 2.0;
     center_x = x1 + rad_x;
     center_y = y1 + rad_y;

     cos_start = cos(start);
     cos_end = cos(end);
     sin_start = sin(start);
     sin_end = sin(end);

     half = (end - start) / 2.0;
     a = 4.0 / 3.0 * (1 - cos(half)) / sin(half);

     if(write_first){
         pt[0].X = cos_start;
         pt[0].Y = sin_start;
     }
     pt[1].X = cos_start - a * sin_start;
     pt[1].Y = sin_start + a * cos_start;

     pt[3].X = cos_end;
     pt[3].Y = sin_end;
     pt[2].X = cos_end + a * sin_end;
     pt[2].Y = sin_end - a * cos_end;

     /* expand the points back from the unit circle to the ellipse */
     for(i = (write_first ? 0 : 1); i < 4; i ++){
         pt[i].X = pt[i].X * rad_x + center_x;
         pt[i].Y = pt[i].Y * rad_y + center_y;
     }
 }

 /* We plot the curve as if it is on a circle then stretch the points.  This
  * adjusts the angles so that when we stretch the points they will end in the
  * right place. This is only complicated because atan and atan2 do not behave
  * conveniently. */
 static void unstretch_angle(REAL * angle, REAL rad_x, REAL rad_y)
 {
     REAL stretched;
     INT revs_off;

     *angle = deg2rad(*angle);

     if(fabs(cos(*angle)) < 0.00001 || fabs(sin(*angle)) < 0.00001)
         return;

     stretched = gdiplus_atan2(sin(*angle) / fabs(rad_y), cos(*angle) / fabs(rad_x));
     revs_off = roundr(*angle / (2.0 * M_PI)) - roundr(stretched / (2.0 * M_PI));
     stretched += ((REAL)revs_off) * M_PI * 2.0;
     *angle = stretched;
 }

 /* Stores the bezier points that correspond to the arc in points.  If points is
  * null, just return the number of points needed to represent the arc. */
 INT arc2polybezier(GpPointF * points, REAL x1, REAL y1, REAL x2, REAL y2,
     REAL startAngle, REAL sweepAngle)
 {
     INT i;
     REAL end_angle, start_angle, endAngle;

     endAngle = startAngle + sweepAngle;
     unstretch_angle(&startAngle, x2 / 2.0, y2 / 2.0);
     unstretch_angle(&endAngle, x2 / 2.0, y2 / 2.0);

     /* start_angle and end_angle are the iterative variables */
     start_angle = startAngle;

     for(i = 0; i < MAX_ARC_PTS - 1; i += 3){
         /* check if we've overshot the end angle */
         if( sweepAngle > 0.0 )
         {
             if (start_angle >= endAngle) break;
             end_angle = min(start_angle + M_PI_2, endAngle);
         }
         else
         {
             if (start_angle <= endAngle) break;
             end_angle = max(start_angle - M_PI_2, endAngle);
         }

         if (points)
             add_arc_part(&points[i], x1, y1, x2, y2, start_angle, end_angle, i == 0);

         start_angle += M_PI_2 * (sweepAngle < 0.0 ? -1.0 : 1.0);
     }

     if (i == 0) return 0;
     else return i+1;
 }

 COLORREF ARGB2COLORREF(ARGB color)
 {
     /*
     Packing of these color structures:
     COLORREF:   00bbggrr
     ARGB:       aarrggbb
     FIXME:doesn't handle alpha channel
     */
     return ((color & 0x0000ff) << 16) +
            (color & 0x00ff00) +
            ((color & 0xff0000) >> 16);
 }

 HBITMAP ARGB2BMP(ARGB color)
 {
     HDC hdc;
     BITMAPINFO bi;
     HBITMAP result;
     RGBQUAD *bits;
     int alpha;

     if ((color & 0xff000000) == 0xff000000) return 0;

     hdc = CreateCompatibleDC(NULL);

     bi.bmiHeader.biSize = sizeof(bi.bmiHeader);
     bi.bmiHeader.biWidth = 1;
     bi.bmiHeader.biHeight = 1;
     bi.bmiHeader.biPlanes = 1;
     bi.bmiHeader.biBitCount = 32;
     bi.bmiHeader.biCompression = BI_RGB;
     bi.bmiHeader.biSizeImage = 0;
     bi.bmiHeader.biXPelsPerMeter = 0;
     bi.bmiHeader.biYPelsPerMeter = 0;
     bi.bmiHeader.biClrUsed = 0;
     bi.bmiHeader.biClrImportant = 0;

     result = CreateDIBSection(hdc, &bi, DIB_RGB_COLORS, (void*)&bits, NULL, 0);

     bits[0].rgbReserved = alpha = (color>>24)&0xff;
     bits[0].rgbRed = ((color>>16)&0xff)*alpha/255;
     bits[0].rgbGreen = ((color>>8)&0xff)*alpha/255;
     bits[0].rgbBlue = (color&0xff)*alpha/255;

     DeleteDC(hdc);

     return result;
 }

 /* Like atan2, but puts angle in correct quadrant if dx is 0. */
 REAL gdiplus_atan2(REAL dy, REAL dx)
 {
     if((dx == 0.0) && (dy != 0.0))
         return dy > 0.0 ? M_PI_2 : -M_PI_2;

     return atan2(dy, dx);
 }

 GpStatus hresult_to_status(HRESULT res)
 {
     switch(res){
         case S_OK:
             return Ok;
         case E_OUTOFMEMORY:
             return OutOfMemory;
         case E_INVALIDARG:
             return InvalidParameter;
         default:
             return GenericError;
     }
 }

 /* converts a given unit to its value in pixels */
 REAL convert_unit(HDC hdc, GpUnit unit)
 {
     switch(unit)
     {
         case UnitInch:
             return (REAL) GetDeviceCaps(hdc, LOGPIXELSX);
         case UnitPoint:
             return ((REAL)GetDeviceCaps(hdc, LOGPIXELSX)) / 72.0;
         case UnitDocument:
             return ((REAL)GetDeviceCaps(hdc, LOGPIXELSX)) / 300.0;
         case UnitMillimeter:
             return ((REAL)GetDeviceCaps(hdc, LOGPIXELSX)) / 25.4;
         case UnitWorld:
             ERR("cannot convert UnitWorld\n");
             return 0.0;
         case UnitPixel:
         case UnitDisplay:
         default:
             return 1.0;
     }
 }

 /* Calculates Bezier points from cardinal spline points. */
 void calc_curve_bezier(CONST GpPointF *pts, REAL tension, REAL *x1,
     REAL *y1, REAL *x2, REAL *y2)
 {
     REAL xdiff, ydiff;

     /* calculate tangent */
     xdiff = pts[2].X - pts[0].X;
     ydiff = pts[2].Y - pts[0].Y;

     /* apply tangent to get control points */
     *x1 = pts[1].X - tension * xdiff;
     *y1 = pts[1].Y - tension * ydiff;
     *x2 = pts[1].X + tension * xdiff;
     *y2 = pts[1].Y + tension * ydiff;
 }

 /* Calculates Bezier points from cardinal spline endpoints. */
 void calc_curve_bezier_endp(REAL xend, REAL yend, REAL xadj, REAL yadj,
     REAL tension, REAL *x, REAL *y)
 {
     /* tangent at endpoints is the line from the endpoint to the adjacent point */
     *x = roundr(tension * (xadj - xend) + xend);
     *y = roundr(tension * (yadj - yend) + yend);
 }

 /* make sure path has enough space for len more points */
 BOOL lengthen_path(GpPath *path, INT len)
 {
     /* initial allocation */
     if(path->datalen == 0){
         path->datalen = len * 2;

         path->pathdata.Points = GdipAlloc(path->datalen * sizeof(PointF));
         if(!path->pathdata.Points)   return FALSE;

         path->pathdata.Types = GdipAlloc(path->datalen);
         if(!path->pathdata.Types){
             GdipFree(path->pathdata.Points);
             return FALSE;
         }
     }
     /* reallocation, double size of arrays */
     else if(path->datalen - path->pathdata.Count < len){
         while(path->datalen - path->pathdata.Count < len)
             path->datalen *= 2;

         path->pathdata.Points = HeapReAlloc(GetProcessHeap(), 0,
             path->pathdata.Points, path->datalen * sizeof(PointF));
         if(!path->pathdata.Points)  return FALSE;

         path->pathdata.Types = HeapReAlloc(GetProcessHeap(), 0,
             path->pathdata.Types, path->datalen);
         if(!path->pathdata.Types)   return FALSE;
     }

     return TRUE;
 }

 void convert_32bppARGB_to_32bppPARGB(UINT width, UINT height,
     BYTE *dst_bits, INT dst_stride, const BYTE *src_bits, INT src_stride)
 {
     UINT x, y;
     for (y=0; y<height; y++)
     {
         const BYTE *src=src_bits+y*src_stride;
         BYTE *dst=dst_bits+y*dst_stride;
         for (x=0; x<width; x++)
         {
             BYTE alpha=src[3];
             *dst++ = *src++ * alpha / 255;
             *dst++ = *src++ * alpha / 255;
             *dst++ = *src++ * alpha / 255;
             *dst++ = *src++;
         }
     }
 }

 /* recursive deletion of GpRegion nodes */
 inline void delete_element(region_element* element)
 {
     switch(element->type)
     {
         case RegionDataRect:
             break;
         case RegionDataPath:
             GdipDeletePath(element->elementdata.pathdata.path);
             break;
         case RegionDataEmptyRect:
         case RegionDataInfiniteRect:
             break;
         default:
             delete_element(element->elementdata.combine.left);
             delete_element(element->elementdata.combine.right);
             GdipFree(element->elementdata.combine.left);
             GdipFree(element->elementdata.combine.right);
             break;
     }
 }

 const char *debugstr_rectf(CONST RectF* rc)
 {
     if (!rc) return "(null)";
     return wine_dbg_sprintf("(%0.2f,%0.2f,%0.2f,%0.2f)", rc->X, rc->Y, rc->Width, rc->Height);
 }
	/*
	* Copyright (C) 2007 Google (Evan Stade)
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
	*/

	#include <stdarg.h>
	#include <math.h>

	#include "windef.h"
	#include "winbase.h"
	#include "winerror.h"
	#include "wine/debug.h"
	#include "wingdi.h"

	#include "objbase.h"

	#include "winreg.h"
	#include "shlwapi.h"

	#include "gdiplus.h"
	#include "gdiplus_private.h"

	WINE_DEFAULT_DEBUG_CHANNEL(gdiplus);

	static Status WINAPI NotificationHook(ULONG_PTR *token)
	{
	TRACE("%p\n", token);
	if(!token)
	return InvalidParameter;

	return Ok;
	}

	static void WINAPI NotificationUnhook(ULONG_PTR token)
	{
	TRACE("%ld\n", token);
	}

	/*****************************************************
	* DllMain
	*/
	BOOL WINAPI DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved)
	{
	TRACE("(%p, %d, %p)\n", hinst, reason, reserved);

	switch(reason)
	{
	case DLL_WINE_PREATTACH:
	return FALSE; /* prefer native version */

	case DLL_PROCESS_ATTACH:
	DisableThreadLibraryCalls( hinst );
	break;

	case DLL_PROCESS_DETACH:
	free_installed_fonts();
	break;
	}
	return TRUE;
	}

	/*****************************************************
	* GdiplusStartup [GDIPLUS.@]
	*/
	Status WINAPI GdiplusStartup(ULONG_PTR token, const struct GdiplusStartupInput input,
	struct GdiplusStartupOutput *output)
	{
	if(!token \|\| !input)
	return InvalidParameter;

	TRACE("%p %p %p\n", token, input, output);
	TRACE("GdiplusStartupInput %d %p %d %d\n", input->GdiplusVersion,
	input->DebugEventCallback, input->SuppressBackgroundThread,
	input->SuppressExternalCodecs);

	if(input->GdiplusVersion < 1 \|\| input->GdiplusVersion > 2)
	return UnsupportedGdiplusVersion;

	if(input->SuppressBackgroundThread){
	if(!output)
	return InvalidParameter;

	output->NotificationHook = NotificationHook;
	output->NotificationUnhook = NotificationUnhook;
	}

	*token = 0xdeadbeef;

	/* FIXME: DebugEventCallback ignored */

	return Ok;
	}

	GpStatus WINAPI GdiplusNotificationHook(ULONG_PTR *token)
	{
	FIXME("%p\n", token);
	return NotificationHook(token);
	}

	void WINAPI GdiplusNotificationUnhook(ULONG_PTR token)
	{
	FIXME("%ld\n", token);
	NotificationUnhook(token);
	}

	/*****************************************************
	* GdiplusShutdown [GDIPLUS.@]
	*/
	void WINAPI GdiplusShutdown(ULONG_PTR token)
	{
	/* FIXME: no object tracking */
	}

	/*****************************************************
	* GdipAlloc [GDIPLUS.@]
	*/
	void* WINGDIPAPI GdipAlloc(SIZE_T size)
	{
	return HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, size);
	}

	/*****************************************************
	* GdipFree [GDIPLUS.@]
	*/
	void WINGDIPAPI GdipFree(void* ptr)
	{
	HeapFree(GetProcessHeap(), 0, ptr);
	}

	/* Calculates the bezier points needed to fill in the arc portion starting at
	* angle start and ending at end. These two angles should be no more than 90
	* degrees from each other. x1, y1, x2, y2 describes the bounding box (upper
	* left and width and height). Angles must be in radians. write_first indicates
	* that the first bezier point should be written out (usually this is false).
	* pt is the array of GpPointFs that gets written to.
	**/
	static void add_arc_part(GpPointF * pt, REAL x1, REAL y1, REAL x2, REAL y2,
	REAL start, REAL end, BOOL write_first)
	{
	REAL center_x, center_y, rad_x, rad_y, cos_start, cos_end,
	sin_start, sin_end, a, half;
	INT i;

	rad_x = x2 / 2.0;
	rad_y = y2 / 2.0;
	center_x = x1 + rad_x;
	center_y = y1 + rad_y;

	cos_start = cos(start);
	cos_end = cos(end);
	sin_start = sin(start);
	sin_end = sin(end);

	half = (end - start) / 2.0;
	a = 4.0 / 3.0 * (1 - cos(half)) / sin(half);

	if(write_first){
	pt[0].X = cos_start;
	pt[0].Y = sin_start;
	}
	pt[1].X = cos_start - a * sin_start;
	pt[1].Y = sin_start + a * cos_start;

	pt[3].X = cos_end;
	pt[3].Y = sin_end;
	pt[2].X = cos_end + a * sin_end;
	pt[2].Y = sin_end - a * cos_end;

	/* expand the points back from the unit circle to the ellipse */
	for(i = (write_first ? 0 : 1); i < 4; i ++){
	pt[i].X = pt[i].X * rad_x + center_x;
	pt[i].Y = pt[i].Y * rad_y + center_y;
	}
	}

	/* We plot the curve as if it is on a circle then stretch the points. This
	* adjusts the angles so that when we stretch the points they will end in the
	* right place. This is only complicated because atan and atan2 do not behave
	* conveniently. */
	static void unstretch_angle(REAL * angle, REAL rad_x, REAL rad_y)
	{
	REAL stretched;
	INT revs_off;

	angle = deg2rad(angle);

	if(fabs(cos(angle)) < 0.00001 \|\| fabs(sin(angle)) < 0.00001)
	return;

	stretched = gdiplus_atan2(sin(angle) / fabs(rad_y), cos(angle) / fabs(rad_x));
	revs_off = roundr(angle / (2.0 M_PI)) - roundr(stretched / (2.0 * M_PI));
	stretched += ((REAL)revs_off) * M_PI * 2.0;
	*angle = stretched;
	}

	/* Stores the bezier points that correspond to the arc in points. If points is
	* null, just return the number of points needed to represent the arc. */
	INT arc2polybezier(GpPointF * points, REAL x1, REAL y1, REAL x2, REAL y2,
	REAL startAngle, REAL sweepAngle)
	{
	INT i;
	REAL end_angle, start_angle, endAngle;

	endAngle = startAngle + sweepAngle;
	unstretch_angle(&startAngle, x2 / 2.0, y2 / 2.0);
	unstretch_angle(&endAngle, x2 / 2.0, y2 / 2.0);

	/* start_angle and end_angle are the iterative variables */
	start_angle = startAngle;

	for(i = 0; i < MAX_ARC_PTS - 1; i += 3){
	/* check if we've overshot the end angle */
	if( sweepAngle > 0.0 )
	{
	if (start_angle >= endAngle) break;
	end_angle = min(start_angle + M_PI_2, endAngle);
	}
	else
	{
	if (start_angle <= endAngle) break;
	end_angle = max(start_angle - M_PI_2, endAngle);
	}

	if (points)
	add_arc_part(&points[i], x1, y1, x2, y2, start_angle, end_angle, i == 0);

	start_angle += M_PI_2 * (sweepAngle < 0.0 ? -1.0 : 1.0);
	}

	if (i == 0) return 0;
	else return i+1;
	}

	COLORREF ARGB2COLORREF(ARGB color)
	{
	/*
	Packing of these color structures:
	COLORREF: 00bbggrr
	ARGB: aarrggbb
	FIXME:doesn't handle alpha channel
	*/
	return ((color & 0x0000ff) << 16) +
	(color & 0x00ff00) +
	((color & 0xff0000) >> 16);
	}

	HBITMAP ARGB2BMP(ARGB color)
	{
	HDC hdc;
	BITMAPINFO bi;
	HBITMAP result;
	RGBQUAD *bits;
	int alpha;

	if ((color & 0xff000000) == 0xff000000) return 0;

	hdc = CreateCompatibleDC(NULL);

	bi.bmiHeader.biSize = sizeof(bi.bmiHeader);
	bi.bmiHeader.biWidth = 1;
	bi.bmiHeader.biHeight = 1;
	bi.bmiHeader.biPlanes = 1;
	bi.bmiHeader.biBitCount = 32;
	bi.bmiHeader.biCompression = BI_RGB;
	bi.bmiHeader.biSizeImage = 0;
	bi.bmiHeader.biXPelsPerMeter = 0;
	bi.bmiHeader.biYPelsPerMeter = 0;
	bi.bmiHeader.biClrUsed = 0;
	bi.bmiHeader.biClrImportant = 0;

	result = CreateDIBSection(hdc, &bi, DIB_RGB_COLORS, (void*)&bits, NULL, 0);

	bits[0].rgbReserved = alpha = (color>>24)&0xff;
	bits[0].rgbRed = ((color>>16)&0xff)*alpha/255;
	bits[0].rgbGreen = ((color>>8)&0xff)*alpha/255;
	bits[0].rgbBlue = (color&0xff)*alpha/255;

	DeleteDC(hdc);

	return result;
	}

	/* Like atan2, but puts angle in correct quadrant if dx is 0. */
	REAL gdiplus_atan2(REAL dy, REAL dx)
	{
	if((dx == 0.0) && (dy != 0.0))
	return dy > 0.0 ? M_PI_2 : -M_PI_2;

	return atan2(dy, dx);
	}

	GpStatus hresult_to_status(HRESULT res)
	{
	switch(res){
	case S_OK:
	return Ok;
	case E_OUTOFMEMORY:
	return OutOfMemory;
	case E_INVALIDARG:
	return InvalidParameter;
	default:
	return GenericError;
	}
	}

	/* converts a given unit to its value in pixels */
	REAL convert_unit(HDC hdc, GpUnit unit)
	{
	switch(unit)
	{
	case UnitInch:
	return (REAL) GetDeviceCaps(hdc, LOGPIXELSX);
	case UnitPoint:
	return ((REAL)GetDeviceCaps(hdc, LOGPIXELSX)) / 72.0;
	case UnitDocument:
	return ((REAL)GetDeviceCaps(hdc, LOGPIXELSX)) / 300.0;
	case UnitMillimeter:
	return ((REAL)GetDeviceCaps(hdc, LOGPIXELSX)) / 25.4;
	case UnitWorld:
	ERR("cannot convert UnitWorld\n");
	return 0.0;
	case UnitPixel:
	case UnitDisplay:
	default:
	return 1.0;
	}
	}

	/* Calculates Bezier points from cardinal spline points. */
	void calc_curve_bezier(CONST GpPointF pts, REAL tension, REAL x1,
	REAL y1, REAL x2, REAL *y2)
	{
	REAL xdiff, ydiff;

	/* calculate tangent */
	xdiff = pts[2].X - pts[0].X;
	ydiff = pts[2].Y - pts[0].Y;

	/* apply tangent to get control points */
	x1 = pts[1].X - tension xdiff;
	y1 = pts[1].Y - tension ydiff;
	x2 = pts[1].X + tension xdiff;
	y2 = pts[1].Y + tension ydiff;
	}

	/* Calculates Bezier points from cardinal spline endpoints. */
	void calc_curve_bezier_endp(REAL xend, REAL yend, REAL xadj, REAL yadj,
	REAL tension, REAL x, REAL y)
	{
	/* tangent at endpoints is the line from the endpoint to the adjacent point */
	x = roundr(tension (xadj - xend) + xend);
	y = roundr(tension (yadj - yend) + yend);
	}

	/* make sure path has enough space for len more points */
	BOOL lengthen_path(GpPath *path, INT len)
	{
	/* initial allocation */
	if(path->datalen == 0){
	path->datalen = len * 2;

	path->pathdata.Points = GdipAlloc(path->datalen * sizeof(PointF));
	if(!path->pathdata.Points) return FALSE;

	path->pathdata.Types = GdipAlloc(path->datalen);
	if(!path->pathdata.Types){
	GdipFree(path->pathdata.Points);
	return FALSE;
	}
	}
	/* reallocation, double size of arrays */
	else if(path->datalen - path->pathdata.Count < len){
	while(path->datalen - path->pathdata.Count < len)
	path->datalen *= 2;

	path->pathdata.Points = HeapReAlloc(GetProcessHeap(), 0,
	path->pathdata.Points, path->datalen * sizeof(PointF));
	if(!path->pathdata.Points) return FALSE;

	path->pathdata.Types = HeapReAlloc(GetProcessHeap(), 0,
	path->pathdata.Types, path->datalen);
	if(!path->pathdata.Types) return FALSE;
	}

	return TRUE;
	}

	void convert_32bppARGB_to_32bppPARGB(UINT width, UINT height,
	BYTE dst_bits, INT dst_stride, const BYTE src_bits, INT src_stride)
	{
	UINT x, y;
	for (y=0; y<height; y++)
	{
	const BYTE src=src_bits+ysrc_stride;
	BYTE dst=dst_bits+ydst_stride;
	for (x=0; x<width; x++)
	{
	BYTE alpha=src[3];
	dst++ = src++ * alpha / 255;
	dst++ = src++ * alpha / 255;
	dst++ = src++ * alpha / 255;
	dst++ = src++;
	}
	}
	}

	/* recursive deletion of GpRegion nodes */
	inline void delete_element(region_element* element)
	{
	switch(element->type)
	{
	case RegionDataRect:
	break;
	case RegionDataPath:
	GdipDeletePath(element->elementdata.pathdata.path);
	break;
	case RegionDataEmptyRect:
	case RegionDataInfiniteRect:
	break;
	default:
	delete_element(element->elementdata.combine.left);
	delete_element(element->elementdata.combine.right);
	GdipFree(element->elementdata.combine.left);
	GdipFree(element->elementdata.combine.right);
	break;
	}
	}

	const char debugstr_rectf(CONST RectF rc)
	{
	if (!rc) return "(null)";
	return wine_dbg_sprintf("(%0.2f,%0.2f,%0.2f,%0.2f)", rc->X, rc->Y, rc->Width, rc->Height);
	}