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[css-values] Define 'device pixel'. #7287
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css-values-3/Overview.bs

Lines changed: 12 additions & 3 deletions
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@@ -1318,12 +1318,12 @@ Absolute Lengths: the ''cm'', ''mm'', ''Q'', ''in'', ''pt'', ''pc'', ''px'' unit
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and devices with unusual viewing distances,
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it is recommended instead that the [=anchor unit=] be the [=pixel unit=].
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For such devices it is recommended that the [=pixel unit=]
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refer to the whole number of device pixels that best approximates the reference pixel.
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refer to the whole number of [=device pixels=] that best approximates the reference pixel.
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Note: If the anchor unit is the pixel unit,
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the physical units might not match their physical measurements.
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Alternatively if the anchor unit is a physical unit,
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the pixel unit might not map to a whole number of device pixels.
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the pixel unit might not map to a whole number of [=device pixels=].
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Note: This definition of the [=pixel unit=] and the [=physical units=]
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differs from the earlier editions of CSS1 and CSS2.
@@ -1347,7 +1347,7 @@ Absolute Lengths: the ''cm'', ''mm'', ''Q'', ''in'', ''pt'', ''pc'', ''px'' unit
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css/CSS2/values/units-009.xht
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The reference pixel is the visual angle of one pixel on a device with a pixel density of 96dpi
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The reference pixel is the visual angle of one pixel on a device with a [=device pixel=] density of 96dpi
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and a distance from the reader of an arm's length.
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For a nominal arm's length of 28 inches,
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the visual angle is therefore about 0.0213 degrees.
@@ -1400,6 +1400,15 @@ Absolute Lengths: the ''cm'', ''mm'', ''Q'', ''in'', ''pt'', ''pc'', ''px'' unit
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css/css-values/absolute-length-units-001.html
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A device pixel is the smallest unit of area on the device output
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capable of displaying its full range of colors.
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For typical color screens, it's a square or somewhat rectangular region
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containing a red, green, and blue subpixel.
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Many non-traditional outputs exist that can blur this definition,
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such as by displaying some colors at higher resolutions.
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Such devices still expose some equivalent notion of "device pixel",
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however.
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Other Quantities
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css-values-4/Overview.bs

Lines changed: 12 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -2272,12 +2272,12 @@ Absolute Lengths: the ''cm'', ''mm'', ''Q'', ''in'', ''pt'', ''pc'', ''px'' unit
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and devices with unusual viewing distances,
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it is recommended instead that the [=anchor unit=] be the [=pixel unit=].
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For such devices it is recommended that the [=pixel unit=]
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refer to the whole number of device pixels that best approximates the reference pixel.
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refer to the whole number of [=device pixels=] that best approximates the reference pixel.
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Note: If the [=anchor unit=] is the [=pixel unit=],
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the [=physical units=] might not match their physical measurements.
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Alternatively if the [=anchor unit=] is a [=physical unit=],
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the [=pixel unit=] might not map to a whole number of device pixels.
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the [=pixel unit=] might not map to a whole number of [=device pixels=].
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Note: This definition of the [=pixel unit=] and the [=physical units=]
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differs from the earlier editions of CSS1 and CSS2.
@@ -2301,7 +2301,7 @@ Absolute Lengths: the ''cm'', ''mm'', ''Q'', ''in'', ''pt'', ''pc'', ''px'' unit
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css/CSS2/values/units-009.xht
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The reference pixel is the visual angle of one pixel on a device with a pixel density of 96dpi
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The reference pixel is the visual angle of one pixel on a device with a [=device pixel=] density of 96dpi
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and a distance from the reader of an arm's length.
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For a nominal arm's length of 28 inches,
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the visual angle is therefore about 0.0213 degrees.
@@ -2354,6 +2354,15 @@ Absolute Lengths: the ''cm'', ''mm'', ''Q'', ''in'', ''pt'', ''pc'', ''px'' unit
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css/css-values/absolute-length-units-001.html
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A device pixel is the smallest unit of area on the device output
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capable of displaying its full range of colors.
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For typical color screens, it's a square or somewhat rectangular region
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containing a red, green, and blue subpixel.
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Many non-traditional outputs exist that can blur this definition,
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such as by displaying some colors at higher resolutions.
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Such devices still expose some equivalent notion of "device pixel",
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however.
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Other Quantities
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