Title: [266266] trunk/Source/WebCore
- Revision
- 266266
- Author
- [email protected]
- Date
- 2020-08-27 18:24:15 -0700 (Thu, 27 Aug 2020)
Log Message
CSS Filter invert() and opacity() Implementation Should Use Linear Transfer Function for Clarity and Simplicity
https://bugs.webkit.org/show_bug.cgi?id=215896
Simplify CSS filters, invert() and opacity() implementation by using "linear" transfer function,
instead of using a more confusing transfer function, "table". For invert(), the transfer function
is type="table" tableValues="[amount] (1 - [amount])", which is equivalent to a linear function
of slope 1 - 2 * [amount] and intercept [amount]; for opacity the transfer function is type="table" tableValues="0 [amount]"
which is equivalent to a linear transfer function of slope [amount] and intercept 0. This change will make the implementation
clearer and simpler.
Patch by Frank Yang <[email protected]> on 2020-08-27
Reviewed by Myles C. Maxfield.
No new tests needed, using existing tests in css/filter-effects
* rendering/CSSFilter.cpp:
(WebCore::CSSFilter::build): Modified the implementation of invert() and opacity() so that they both use
a linear component transfer function instead of a more confusing table transfer function.
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (266265 => 266266)
--- trunk/Source/WebCore/ChangeLog 2020-08-28 01:18:07 UTC (rev 266265)
+++ trunk/Source/WebCore/ChangeLog 2020-08-28 01:24:15 UTC (rev 266266)
@@ -1,3 +1,24 @@
+2020-08-27 Frank Yang <[email protected]>
+
+ CSS Filter invert() and opacity() Implementation Should Use Linear Transfer Function for Clarity and Simplicity
+ https://bugs.webkit.org/show_bug.cgi?id=215896
+
+ Simplify CSS filters, invert() and opacity() implementation by using "linear" transfer function,
+ instead of using a more confusing transfer function, "table". For invert(), the transfer function
+ is type="table" tableValues="[amount] (1 - [amount])", which is equivalent to a linear function
+ of slope 1 - 2 * [amount] and intercept [amount]; for opacity the transfer function is type="table" tableValues="0 [amount]"
+ which is equivalent to a linear transfer function of slope [amount] and intercept 0. This change will make the implementation
+ clearer and simpler.
+
+ Reviewed by Myles C. Maxfield.
+
+ No new tests needed, using existing tests in css/filter-effects
+
+ * rendering/CSSFilter.cpp:
+ (WebCore::CSSFilter::build): Modified the implementation of invert() and opacity() so that they both use
+ a linear component transfer function instead of a more confusing table transfer function.
+
+
2020-08-27 Devin Rousso <[email protected]>
[iOS] provide a way to get previously inserted alternatives for the selected text
Modified: trunk/Source/WebCore/rendering/CSSFilter.cpp (266265 => 266266)
--- trunk/Source/WebCore/rendering/CSSFilter.cpp 2020-08-28 01:18:07 UTC (rev 266265)
+++ trunk/Source/WebCore/rendering/CSSFilter.cpp 2020-08-28 01:24:15 UTC (rev 266266)
@@ -221,11 +221,10 @@
case FilterOperation::INVERT: {
auto& componentTransferOperation = downcast<BasicComponentTransferFilterOperation>(filterOperation);
ComponentTransferFunction transferFunction;
- transferFunction.type = FECOMPONENTTRANSFER_TYPE_TABLE;
- Vector<float> transferParameters;
- transferParameters.append(narrowPrecisionToFloat(componentTransferOperation.amount()));
- transferParameters.append(narrowPrecisionToFloat(1 - componentTransferOperation.amount()));
- transferFunction.tableValues = transferParameters;
+ transferFunction.type = FECOMPONENTTRANSFER_TYPE_LINEAR;
+ float amount = narrowPrecisionToFloat(componentTransferOperation.amount());
+ transferFunction.slope = 1 - 2 * amount;
+ transferFunction.intercept = amount;
ComponentTransferFunction nullFunction;
effect = FEComponentTransfer::create(*this, transferFunction, transferFunction, transferFunction, nullFunction);
@@ -237,11 +236,10 @@
case FilterOperation::OPACITY: {
auto& componentTransferOperation = downcast<BasicComponentTransferFilterOperation>(filterOperation);
ComponentTransferFunction transferFunction;
- transferFunction.type = FECOMPONENTTRANSFER_TYPE_TABLE;
- Vector<float> transferParameters;
- transferParameters.append(0);
- transferParameters.append(narrowPrecisionToFloat(componentTransferOperation.amount()));
- transferFunction.tableValues = transferParameters;
+ transferFunction.type = FECOMPONENTTRANSFER_TYPE_LINEAR;
+ float amount = narrowPrecisionToFloat(componentTransferOperation.amount());
+ transferFunction.slope = amount;
+ transferFunction.intercept = 0;
ComponentTransferFunction nullFunction;
effect = FEComponentTransfer::create(*this, nullFunction, nullFunction, nullFunction, transferFunction);
_______________________________________________
webkit-changes mailing list
[email protected]
https://lists.webkit.org/mailman/listinfo/webkit-changes
