PRBool
nsThebesDeviceContext::SetPixelScale(float aScale)
{
if (aScale <= 0) {
NS_NOTREACHED("Invalid pixel scale value");
return PR_FALSE;
}
PRInt32 oldAppUnitsPerDevPixel = mAppUnitsPerDevPixel;
mPixelScale = aScale;
UpdateScaledAppUnits();
return oldAppUnitsPerDevPixel != mAppUnitsPerDevPixel;
}
nsresult
nsThebesDeviceContext::SetDPI()
{
PRInt32 dpi = -1;
PRBool dotsArePixels = PR_TRUE;
// The number of device pixels per CSS pixel. A value <= 0 means choose
// automatically based on the DPI. A positive value is used as-is. This effectively
// controls the size of a CSS "px".
float prefDevPixelsPerCSSPixel = -1.0;
nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
if (prefs) {
nsXPIDLCString prefString;
nsresult rv = prefs->GetCharPref("layout.css.devPixelsPerPx", getter_Copies(prefString));
if (NS_SUCCEEDED(rv) && !prefString.IsEmpty()) {
prefDevPixelsPerCSSPixel = static_cast<float>(atof(prefString));
}
}
// PostScript, PDF and Mac (when printing) all use 72 dpi
// Use a printing DC to determine the other dpi values
if (mPrintingSurface) {
switch (mPrintingSurface->GetType()) {
case gfxASurface::SurfaceTypePDF:
case gfxASurface::SurfaceTypePS:
case gfxASurface::SurfaceTypeQuartz:
dpi = 72;
break;
#ifdef XP_WIN
case gfxASurface::SurfaceTypeWin32:
case gfxASurface::SurfaceTypeWin32Printing: {
PRInt32 OSVal = GetDeviceCaps(GetPrintHDC(), LOGPIXELSY);
dpi = 144;
mPrintingScale = float(OSVal) / dpi;
break;
}
#endif
#ifdef XP_OS2
case gfxASurface::SurfaceTypeOS2:
LONG lDPI;
if (DevQueryCaps(GetPrintHDC(), CAPS_VERTICAL_FONT_RES, 1, &lDPI))
dpi = lDPI;
break;
#endif
default:
NS_NOTREACHED("Unexpected printing surface type");
break;
}
dotsArePixels = PR_FALSE;
} else {
nsresult rv;
// A value of -1 means use the minimum of 96 and the system DPI.
// A value of 0 means use the system DPI. A positive value is used as the DPI.
// This sets the physical size of a device pixel and thus controls the
// interpretation of physical units such as "pt".
PRInt32 prefDPI = -1;
if (prefs) {
rv = prefs->GetIntPref("layout.css.dpi", &prefDPI);
if (NS_FAILED(rv)) {
prefDPI = -1;
}
}
dpi = gfxPlatform::GetDPI();
#ifdef MOZ_ENABLE_GTK2
if (prefDPI < 0) // Clamp the minimum dpi to 96dpi
dpi = PR_MAX(dpi, 96);
#endif
if (prefDPI > 0 && !mPrintingSurface)
dpi = prefDPI;
}
NS_ASSERTION(dpi != -1, "no dpi set");
if (dotsArePixels) {
if (prefDevPixelsPerCSSPixel <= 0) {
// Round down to multiple of 96, which is the number of dev pixels
// per CSS pixel. Then, divide that into AppUnitsPerCSSPixel()
// to get the number of app units per dev pixel. The PR_MAXes are
// to make sure we don't end up dividing by zero.
PRUint32 roundedDPIScaleFactor = dpi/96;
mAppUnitsPerDevNotScaledPixel =
PR_MAX(1, AppUnitsPerCSSPixel() / PR_MAX(1, roundedDPIScaleFactor));
} else {
mAppUnitsPerDevNotScaledPixel =
PR_MAX(1, static_cast<PRInt32>(AppUnitsPerCSSPixel() /
prefDevPixelsPerCSSPixel));
}
} else {
/* set mAppUnitsPerDevPixel so we're using exactly 72 dpi, even
* though that means we have a non-integer number of device "pixels"
* per CSS pixel
*/
mAppUnitsPerDevNotScaledPixel = (AppUnitsPerCSSPixel() * 96) / dpi;
}
mAppUnitsPerInch = NSIntPixelsToAppUnits(dpi, mAppUnitsPerDevNotScaledPixel);
UpdateScaledAppUnits();
return NS_OK;
}
nsresult
nsThebesDeviceContext::SetDPI()
{
float dpi = -1.0f;
// PostScript, PDF and Mac (when printing) all use 72 dpi
// Use a printing DC to determine the other dpi values
if (mPrintingSurface) {
switch (mPrintingSurface->GetType()) {
case gfxASurface::SurfaceTypePDF:
case gfxASurface::SurfaceTypePS:
case gfxASurface::SurfaceTypeQuartz:
dpi = 72.0f;
break;
#ifdef XP_WIN
case gfxASurface::SurfaceTypeWin32:
case gfxASurface::SurfaceTypeWin32Printing: {
PRInt32 OSVal = GetDeviceCaps(GetPrintHDC(), LOGPIXELSY);
dpi = 144.0f;
mPrintingScale = float(OSVal) / dpi;
break;
}
#endif
#ifdef XP_OS2
case gfxASurface::SurfaceTypeOS2:
LONG lDPI;
if (DevQueryCaps(GetPrintHDC(), CAPS_VERTICAL_FONT_RES, 1, &lDPI))
dpi = lDPI;
break;
#endif
default:
NS_NOTREACHED("Unexpected printing surface type");
break;
}
mAppUnitsPerDevNotScaledPixel =
NS_lround((AppUnitsPerCSSPixel() * 96) / dpi);
} else {
nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
// A value of -1 means use the maximum of 96 and the system DPI.
// A value of 0 means use the system DPI. A positive value is used as the DPI.
// This sets the physical size of a device pixel and thus controls the
// interpretation of physical units.
PRInt32 prefDPI = -1;
if (prefs) {
nsresult rv = prefs->GetIntPref("layout.css.dpi", &prefDPI);
if (NS_FAILED(rv)) {
prefDPI = -1;
}
}
if (prefDPI > 0) {
dpi = prefDPI;
} else if (mWidget) {
dpi = mWidget->GetDPI();
if (prefDPI < 0) {
dpi = PR_MAX(96.0f, dpi);
}
} else {
dpi = 96.0f;
}
// The number of device pixels per CSS pixel. A value <= 0 means choose
// automatically based on the DPI. A positive value is used as-is. This effectively
// controls the size of a CSS "px".
float devPixelsPerCSSPixel = -1.0;
if (prefs) {
nsXPIDLCString prefString;
nsresult rv = prefs->GetCharPref("layout.css.devPixelsPerPx", getter_Copies(prefString));
if (NS_SUCCEEDED(rv) && !prefString.IsEmpty()) {
devPixelsPerCSSPixel = static_cast<float>(atof(prefString));
}
}
if (devPixelsPerCSSPixel <= 0) {
if (mWidget) {
devPixelsPerCSSPixel = mWidget->GetDefaultScale();
} else {
devPixelsPerCSSPixel = 1.0;
}
}
mAppUnitsPerDevNotScaledPixel =
PR_MAX(1, NS_lround(AppUnitsPerCSSPixel() / devPixelsPerCSSPixel));
}
NS_ASSERTION(dpi != -1.0, "no dpi set");
mAppUnitsPerPhysicalInch = NS_lround(dpi * mAppUnitsPerDevNotScaledPixel);
UpdateScaledAppUnits();
return NS_OK;
}
