12044 2011-02-12 00:08:25 +0000 Feature request: Give developers an option to disable a context's image smoothing 2012-03-28 21:46:15 +0000 1 1 1 Unclassified HTML WG LC1 HTML Canvas 2D Context unspecified All All RESOLVED FIXED http://www.whatwg.org/specs/web-apps/current-work/#top canvas v5 P3 enhancement --- 1 contributor ian bzbarsky ian jackalmage mike public-html-admin public-html-wg-issue-tracking stack413 public-html-bugzilla oldest_to_newest 45414 0 contributor 2011-02-12 00:08:25 +0000 Specification: Section: http://www.whatwg.org/specs/web-apps/current-work/complete.html#top Comment: This is a new feature request. Request overview: Give developers an option to disable a context's image smoothing (ie, anti-assailing). Problem: When scaling up images, most user agents smooth the output. This is fine for most use cases, but is undesirable when "pixel-perfect" output is desired. Unfortunately, there is nothing in the spec that allows a user to turn off this smoothing. I ran into this issue when I was creating a canvas based image editor. In particular, it more or less torpedoed my first attempt at creating a zoom feature. Simply put, when I tried to show a "zoomed in" view of a smaller base image, the "pixels" of the zoomed view were anti-assailed and bled into each other. The effect was ugly and (more importantly) non-representative of the actual image being edited, which nicely defeated the purpose of an image editor. Currently the only solution is to roll your own scaling algorithms based on imageData, which is less than ideal. Use cases: Any application where a developer needs "pixel perfect" scaling. Examples include image editors, pixel art, pixel animations, and cases where developers want to avoid any computational overhead associated with smoothing. Solution: Codify an existing implementation (see below). My image editor looked great in Firefox! A more complicated solution could allow a developer to specify a specific smoothing algorithm. Something along the lines of "context.smoothing('bicubic')." Existing implementation: "Gecko 1.9.2 introduced the mozImageSmoothingEnabled property to the canvas element; if this Boolean value is false, images won't be smoothed when scaled. This property is true by default." Source: https://developer.mozilla.org/en/Canvas_tutorial/Using_images#Controlling_imag e_scaling_behavior Posted from: 65.185.139.106 45417 1 stack413 2011-02-12 00:14:13 +0000 Sorry this clobbeed 45420 2 jackalmage 2011-02-12 00:30:48 +0000 This is handled in CSS through the 'image-rendering' property <http://dev.w3.org/csswg/css3-images/#image-rendering>. It would be nice to hook into this. 45659 3 ian 2011-02-16 08:27:18 +0000 EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Partially Accepted Change Description: none yet Rationale: I don't usually like this kind of feature, because it relies on authors making good judgements and that has historically not been a successful strategy for Web browser vendors. However, in this particular case the issue isn't really about optimisation (as it is for 'image-rendering'), it's about a very concrete desire to actually see the pixels blown up. This is something we probably _should_ address. I've marked this "LATER", so we don't lose track of it. However, now is not a great time to add this, because before adding more new features we should first let the browsers catch up to what we've already specced. 52660 4 mike 2011-08-04 05:03:28 +0000 mass-move component to LC1 64750 5 ian 2012-02-29 18:53:22 +0000 Just adding context.imageSmoothingEnabled = boolean seems reasonable. 64786 6 ian 2012-02-29 22:50:14 +0000 Current proposal at: http://wiki.whatwg.org/wiki/Canvas#Image_smoothing 66188 7 ian 2012-03-28 21:46:15 +0000 EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Accepted Change Description: imageSmoothingEnabled for drawImage Rationale: Concurred with reporter's comments.