[giow] (1) Allow UAs to use algorithms other than nearest-neighbour w…

…hen scaling images down.

Affected topics: Canvas

git-svn-id: http://svn.whatwg.org/webapps@8132 340c8d12-0b0e-0410-8428-c7bf67bfef74

complete.html

@@ -36338,11 +36338,12 @@ <h6 id=fill-and-stroke-styles><span class=secno>4.8.11.2.10 </span>Fill and stro
     behavior is "<code title="">repeat-y</code>", or in all four directions all over the bitmap, if
     the repetition behavior is "<code title="">repeat</code>".</p>
 
+<!--CLEANUP-->
     <p>If the original image data is a bitmap image, the value painted at a point in the area of the
-    repetitions is computed by filtering the original image data. If the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code> attribute is set to
-    true, then the user agent may use any filtering algorithm (for example bilinear interpolation or
-    nearest-neighbor). If the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code> attribute is set to
-    false, the image must be rendered using nearest-neighbor interpolation. When such a filtering
+    repetitions is computed by filtering the original image data. When scaling up, if the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code> attribute is set to
+    true, the image must be rendered using nearest-neighbor interpolation. Otherwise, the user agent
+    may use any filtering algorithm (for example bilinear interpolation or nearest-neighbor). When
+    such a filtering
     algorithm requires a pixel value from outside the original image data, it must instead use the
     value from wrapping the pixel's coordinates to the original image's dimensions. (That is, the
     filter uses 'repeat' behavior, regardless of the value of the pattern's repetition behavior.)</p>
@@ -37314,13 +37315,13 @@ <h6 id=drawing-images><span class=secno>4.8.11.2.14 </span>Drawing images</h6>
     negative. <!-- note: that last sentence has several times been needed to correct people who
     suggested that 5,5,-2,-2 was different than 3,3,2,2 --></p>
 
-    <p>If the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
-    attribute is set to true, then the user agent should attempt to apply a smoothing algorithm to
+    <p>When scaling up, if the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
+    attribute is set to true, the user agent should attempt to apply a smoothing algorithm to
     the image data when it is scaled. Otherwise, the image must be rendered using nearest-neighbor
     interpolation.</p>
 
     <p class=note>This specification does not define the precise algorithm to use when scaling an
-    image when the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
+    image down, or when scaling an image up when the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
     attribute is set to true.</p>
 
     <p class=note>When a <code><a href=#the-canvas-element>canvas</a></code> or <code><a href=#canvasrenderingcontext2d>CanvasRenderingContext2D</a></code> object is
@@ -38484,7 +38485,7 @@ <h6 id=image-smoothing><span class=secno>4.8.11.2.18 </span>Image smoothing</h6>
    <dd>
 
     <p>Returns whether pattern fills and the <code title=dom-context-2d-drawImage><a href=#dom-context-2d-drawimage>drawImage()</a></code> method will attempt to smooth images if
-    their pixels don't line up exactly with the display.</p>
+    their pixels don't line up exactly with the display, when scaling images up.</p>
 
     <p>Can be set, to change whether images are smoothed (true) or not (false).</p>
 

index

@@ -36338,11 +36338,12 @@ try {
     behavior is "<code title="">repeat-y</code>", or in all four directions all over the bitmap, if
     the repetition behavior is "<code title="">repeat</code>".</p>
 
+<!--CLEANUP-->
     <p>If the original image data is a bitmap image, the value painted at a point in the area of the
-    repetitions is computed by filtering the original image data. If the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code> attribute is set to
-    true, then the user agent may use any filtering algorithm (for example bilinear interpolation or
-    nearest-neighbor). If the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code> attribute is set to
-    false, the image must be rendered using nearest-neighbor interpolation. When such a filtering
+    repetitions is computed by filtering the original image data. When scaling up, if the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code> attribute is set to
+    true, the image must be rendered using nearest-neighbor interpolation. Otherwise, the user agent
+    may use any filtering algorithm (for example bilinear interpolation or nearest-neighbor). When
+    such a filtering
     algorithm requires a pixel value from outside the original image data, it must instead use the
     value from wrapping the pixel's coordinates to the original image's dimensions. (That is, the
     filter uses 'repeat' behavior, regardless of the value of the pattern's repetition behavior.)</p>
@@ -37314,13 +37315,13 @@ v6DVT (also check for '- -' bits in the part above) --><p>The <dfn id=dom-contex
     negative. <!-- note: that last sentence has several times been needed to correct people who
     suggested that 5,5,-2,-2 was different than 3,3,2,2 --></p>
 
-    <p>If the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
-    attribute is set to true, then the user agent should attempt to apply a smoothing algorithm to
+    <p>When scaling up, if the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
+    attribute is set to true, the user agent should attempt to apply a smoothing algorithm to
     the image data when it is scaled. Otherwise, the image must be rendered using nearest-neighbor
     interpolation.</p>
 
     <p class=note>This specification does not define the precise algorithm to use when scaling an
-    image when the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
+    image down, or when scaling an image up when the <code title=dom-context-2d-imageSmoothingEnabled><a href=#dom-context-2d-imagesmoothingenabled>imageSmoothingEnabled</a></code>
     attribute is set to true.</p>
 
     <p class=note>When a <code><a href=#the-canvas-element>canvas</a></code> or <code><a href=#canvasrenderingcontext2d>CanvasRenderingContext2D</a></code> object is
@@ -38484,7 +38485,7 @@ function AddCloud(data, x, y) { ... }</pre>
    <dd>
 
     <p>Returns whether pattern fills and the <code title=dom-context-2d-drawImage><a href=#dom-context-2d-drawimage>drawImage()</a></code> method will attempt to smooth images if
-    their pixels don't line up exactly with the display.</p>
+    their pixels don't line up exactly with the display, when scaling images up.</p>
 
     <p>Can be set, to change whether images are smoothed (true) or not (false).</p>
 

source

@@ -39570,13 +39570,13 @@ try {
     behavior is "<code title="">repeat-y</code>", or in all four directions all over the bitmap, if
     the repetition behavior is "<code title="">repeat</code>".</p>
 
+<!--CLEANUP-->
     <p>If the original image data is a bitmap image, the value painted at a point in the area of the
-    repetitions is computed by filtering the original image data. If the <code
-    title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code> attribute is set to
-    true, then the user agent may use any filtering algorithm (for example bilinear interpolation or
-    nearest-neighbor). If the <code
+    repetitions is computed by filtering the original image data. When scaling up, if the <code
     title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code> attribute is set to
-    false, the image must be rendered using nearest-neighbor interpolation. When such a filtering
+    true, the image must be rendered using nearest-neighbor interpolation. Otherwise, the user agent
+    may use any filtering algorithm (for example bilinear interpolation or nearest-neighbor). When
+    such a filtering
     algorithm requires a pixel value from outside the original image data, it must instead use the
     value from wrapping the pixel's coordinates to the original image's dimensions. (That is, the
     filter uses 'repeat' behavior, regardless of the value of the pattern's repetition behavior.)</p>
@@ -40708,13 +40708,13 @@ v6DVT (also check for '- -' bits in the part above) -->
     negative. <!-- note: that last sentence has several times been needed to correct people who
     suggested that 5,5,-2,-2 was different than 3,3,2,2 --></p>
 
-    <p>If the <code title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
-    attribute is set to true, then the user agent should attempt to apply a smoothing algorithm to
+    <p>When scaling up, if the <code title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
+    attribute is set to true, the user agent should attempt to apply a smoothing algorithm to
     the image data when it is scaled. Otherwise, the image must be rendered using nearest-neighbor
     interpolation.</p>
 
     <p class="note">This specification does not define the precise algorithm to use when scaling an
-    image when the <code title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
+    image down, or when scaling an image up when the <code title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
     attribute is set to true.</p>
 
     <p class="note">When a <code>canvas</code> or <code>CanvasRenderingContext2D</code> object is
@@ -42117,7 +42117,7 @@ function AddCloud(data, x, y) { ... }</pre>
 
     <p>Returns whether pattern fills and the <code
     title="dom-context-2d-drawImage">drawImage()</code> method will attempt to smooth images if
-    their pixels don't line up exactly with the display.</p>
+    their pixels don't line up exactly with the display, when scaling images up.</p>
 
     <p>Can be set, to change whether images are smoothed (true) or not (false).</p>