pjs/layout/style/nsMediaFeatures.cpp

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/* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is nsMediaFeatures.
*
* The Initial Developer of the Original Code is the Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2008
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* L. David Baron <dbaron@dbaron.org>, Mozilla Corporation (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* the features that media queries can test */
#include "nsMediaFeatures.h"
#include "nsGkAtoms.h"
#include "nsCSSKeywords.h"
#include "nsStyleConsts.h"
#include "nsPresContext.h"
#include "nsIDeviceContext.h"
#include "nsCSSValue.h"
#include "nsIDocShell.h"
#include "nsLayoutUtils.h"
static const PRInt32 kOrientationKeywords[] = {
eCSSKeyword_portrait, NS_STYLE_ORIENTATION_PORTRAIT,
eCSSKeyword_landscape, NS_STYLE_ORIENTATION_LANDSCAPE,
eCSSKeyword_UNKNOWN, -1
};
static const PRInt32 kScanKeywords[] = {
eCSSKeyword_progressive, NS_STYLE_SCAN_PROGRESSIVE,
eCSSKeyword_interlace, NS_STYLE_SCAN_INTERLACE,
eCSSKeyword_UNKNOWN, -1
};
PR_STATIC_CALLBACK(nsresult)
GetWidth(nsPresContext* aPresContext, nsCSSValue& aResult)
{
nscoord width = aPresContext->GetVisibleArea().width;
float pixelWidth = aPresContext->AppUnitsToFloatCSSPixels(width);
aResult.SetFloatValue(pixelWidth, eCSSUnit_Pixel);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetHeight(nsPresContext* aPresContext, nsCSSValue& aResult)
{
nscoord height = aPresContext->GetVisibleArea().height;
float pixelHeight = aPresContext->AppUnitsToFloatCSSPixels(height);
aResult.SetFloatValue(pixelHeight, eCSSUnit_Pixel);
return NS_OK;
}
static nsIDeviceContext*
GetDeviceContextFor(nsPresContext* aPresContext)
{
// Do this dance rather than aPresContext->DeviceContext() to get
// things right in multi-monitor situations.
// (It's not clear if this is really needed for GetDepth and GetColor,
// but do it anyway.)
nsIDeviceContext* ctx = nsLayoutUtils::GetDeviceContextForScreenInfo(
nsCOMPtr<nsIDocShell>(do_QueryInterface(
nsCOMPtr<nsISupports>(aPresContext->GetContainer()))));
if (!ctx) {
ctx = aPresContext->DeviceContext();
}
return ctx;
}
PR_STATIC_CALLBACK(nsresult)
GetDeviceWidth(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// XXX: I'm not sure if this is really the right thing for print:
// do we want to include unprintable areas / page margins?
nsIDeviceContext *dx = GetDeviceContextFor(aPresContext);
nscoord width, height;
dx->GetDeviceSurfaceDimensions(width, height);
float pixelWidth = aPresContext->AppUnitsToFloatCSSPixels(width);
aResult.SetFloatValue(pixelWidth, eCSSUnit_Pixel);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetDeviceHeight(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// XXX: I'm not sure if this is really the right thing for print:
// do we want to include unprintable areas / page margins?
nsIDeviceContext *dx = GetDeviceContextFor(aPresContext);
nscoord width, height;
dx->GetDeviceSurfaceDimensions(width, height);
float pixelHeight = aPresContext->AppUnitsToFloatCSSPixels(height);
aResult.SetFloatValue(pixelHeight, eCSSUnit_Pixel);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetOrientation(nsPresContext* aPresContext, nsCSSValue& aResult)
{
nsSize size = aPresContext->GetVisibleArea().Size();
PRInt32 orientation;
if (size.width > size.height) {
orientation = NS_STYLE_ORIENTATION_LANDSCAPE;
} else {
// Per spec, square viewports should be 'portrait'
orientation = NS_STYLE_ORIENTATION_PORTRAIT;
}
aResult.SetIntValue(orientation, eCSSUnit_Enumerated);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetAspectRatio(nsPresContext* aPresContext, nsCSSValue& aResult)
{
nsRefPtr<nsCSSValue::Array> a = nsCSSValue::Array::Create(2);
NS_ENSURE_TRUE(a, NS_ERROR_OUT_OF_MEMORY);
nsSize size = aPresContext->GetVisibleArea().Size();
a->Item(0).SetIntValue(size.width, eCSSUnit_Integer);
a->Item(1).SetIntValue(size.height, eCSSUnit_Integer);
aResult.SetArrayValue(a, eCSSUnit_Array);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetDeviceAspectRatio(nsPresContext* aPresContext, nsCSSValue& aResult)
{
nsRefPtr<nsCSSValue::Array> a = nsCSSValue::Array::Create(2);
NS_ENSURE_TRUE(a, NS_ERROR_OUT_OF_MEMORY);
// XXX: I'm not sure if this is really the right thing for print:
// do we want to include unprintable areas / page margins?
nsIDeviceContext *dx = GetDeviceContextFor(aPresContext);
nscoord width, height;
dx->GetDeviceSurfaceDimensions(width, height);
a->Item(0).SetIntValue(width, eCSSUnit_Integer);
a->Item(1).SetIntValue(height, eCSSUnit_Integer);
aResult.SetArrayValue(a, eCSSUnit_Array);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetColor(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// FIXME: This implementation is bogus. nsThebesDeviceContext
// doesn't provide reliable information (should be fixed in bug
// 424386).
// FIXME: On a monochrome device, return 0!
nsIDeviceContext *dx = GetDeviceContextFor(aPresContext);
PRUint32 depth;
dx->GetDepth(depth);
// Some graphics backends may claim 32-bit depth when it's really 24
// (because they're counting the Alpha component).
if (depth == 32) {
depth = 24;
}
// The spec says to use bits *per color component*, so divide by 3,
// and round down, since the spec says to use the smallest when the
// color components differ.
depth /= 3;
aResult.SetIntValue(PRInt32(depth), eCSSUnit_Integer);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetColorIndex(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// We should return zero if the device does not use a color lookup
// table. Stuart says that our handling of displays with 8-bit
// color is bad enough that we never change the lookup table to
// match what we're trying to display, so perhaps we should always
// return zero. Given that there isn't any better information
// exposed, we don't have much other choice.
aResult.SetIntValue(0, eCSSUnit_Integer);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetMonochrome(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// For color devices we should return 0.
// FIXME: On a monochrome device, return the actual color depth, not
// 0!
aResult.SetIntValue(0, eCSSUnit_Integer);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetResolution(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// Resolution values are in device pixels, not CSS pixels.
nsIDeviceContext *dx = GetDeviceContextFor(aPresContext);
float dpi = float(dx->AppUnitsPerInch()) / float(dx->AppUnitsPerDevPixel());
aResult.SetFloatValue(dpi, eCSSUnit_Inch);
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetScan(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// Since Gecko doesn't support the 'tv' media type, the 'scan'
// feature is never present.
aResult.Reset();
return NS_OK;
}
PR_STATIC_CALLBACK(nsresult)
GetGrid(nsPresContext* aPresContext, nsCSSValue& aResult)
{
// Gecko doesn't support grid devices (e.g., ttys), so the 'grid'
// feature is always 0.
aResult.SetIntValue(0, eCSSUnit_Integer);
return NS_OK;
}
/*
* Adding new media features requires (1) adding the new feature to this
* array, with appropriate entries (and potentially any new code needed
* to support new types in these entries and (2) ensuring that either
* nsPresContext::MediaFeatureValuesChanged or
* nsPresContext::PostMediaFeatureValuesChangedEvent is called when the
* value that would be returned by the entry's mGetter changes.
*/
/* static */ const nsMediaFeature
nsMediaFeatures::features[] = {
{
&nsGkAtoms::width,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eLength,
nsnull,
GetWidth
},
{
&nsGkAtoms::height,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eLength,
nsnull,
GetHeight
},
{
&nsGkAtoms::deviceWidth,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eLength,
nsnull,
GetDeviceWidth
},
{
&nsGkAtoms::deviceHeight,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eLength,
nsnull,
GetDeviceHeight
},
{
&nsGkAtoms::orientation,
nsMediaFeature::eMinMaxNotAllowed,
nsMediaFeature::eEnumerated,
kOrientationKeywords,
GetOrientation
},
{
&nsGkAtoms::aspectRatio,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eIntRatio,
nsnull,
GetAspectRatio
},
{
&nsGkAtoms::deviceAspectRatio,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eIntRatio,
nsnull,
GetDeviceAspectRatio
},
{
&nsGkAtoms::color,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eInteger,
nsnull,
GetColor
},
{
&nsGkAtoms::colorIndex,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eInteger,
nsnull,
GetColorIndex
},
{
&nsGkAtoms::monochrome,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eInteger,
nsnull,
GetMonochrome
},
{
&nsGkAtoms::resolution,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eResolution,
nsnull,
GetResolution
},
{
&nsGkAtoms::scan,
nsMediaFeature::eMinMaxNotAllowed,
nsMediaFeature::eEnumerated,
kScanKeywords,
GetScan
},
{
&nsGkAtoms::grid,
nsMediaFeature::eMinMaxNotAllowed,
nsMediaFeature::eBoolInteger,
nsnull,
GetGrid
},
// Null-mName terminator:
{
nsnull,
nsMediaFeature::eMinMaxAllowed,
nsMediaFeature::eInteger,
nsnull,
nsnull
},
};