{"action":"created","issue":{"url":"https://api.github.com/repos/matplotlib/matplotlib/issues/5603","labels_url":"https://api.github.com/repos/matplotlib/matplotlib/issues/5603/labels{/name}","comments_url":"https://api.github.com/repos/matplotlib/matplotlib/issues/5603/comments","events_url":"https://api.github.com/repos/matplotlib/matplotlib/issues/5603/events","html_url":"https://github.com/matplotlib/matplotlib/pull/5603","id":119945173,"number":5603,"title":"Draw markers around center of pixels","user":{"login":"mdboom","id":38294,"avatar_url":"https://avatars.githubusercontent.com/u/38294?v=3","gravatar_id":"","url":"https://api.github.com/users/mdboom","html_url":"https://github.com/mdboom","followers_url":"https://api.github.com/users/mdboom/followers","following_url":"https://api.github.com/users/mdboom/following{/other_user}","gists_url":"https://api.github.com/users/mdboom/gists{/gist_id}","starred_url":"https://api.github.com/users/mdboom/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mdboom/subscriptions","organizations_url":"https://api.github.com/users/mdboom/orgs","repos_url":"https://api.github.com/users/mdboom/repos","events_url":"https://api.github.com/users/mdboom/events{/privacy}","received_events_url":"https://api.github.com/users/mdboom/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/matplotlib/matplotlib/labels/needs_review","name":"needs_review","color":"009800"}],"state":"open","locked":false,"assignee":null,"milestone":{"url":"https://api.github.com/repos/matplotlib/matplotlib/milestones/21","html_url":"https://github.com/matplotlib/matplotlib/milestones/Critical%20bugfix%20release%20(1.5.1)","labels_url":"https://api.github.com/repos/matplotlib/matplotlib/milestones/21/labels","id":1385613,"number":21,"title":"Critical bugfix release (1.5.1)","description":"","creator":{"login":"mdboom","id":38294,"avatar_url":"https://avatars.githubusercontent.com/u/38294?v=3","gravatar_id":"","url":"https://api.github.com/users/mdboom","html_url":"https://github.com/mdboom","followers_url":"https://api.github.com/users/mdboom/followers","following_url":"https://api.github.com/users/mdboom/following{/other_user}","gists_url":"https://api.github.com/users/mdboom/gists{/gist_id}","starred_url":"https://api.github.com/users/mdboom/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mdboom/subscriptions","organizations_url":"https://api.github.com/users/mdboom/orgs","repos_url":"https://api.github.com/users/mdboom/repos","events_url":"https://api.github.com/users/mdboom/events{/privacy}","received_events_url":"https://api.github.com/users/mdboom/received_events","type":"User","site_admin":false},"open_issues":20,"closed_issues":40,"state":"open","created_at":"2015-10-30T15:12:24Z","updated_at":"2015-12-02T14:58:18Z","due_on":null,"closed_at":null},"comments":5,"created_at":"2015-12-02T13:52:22Z","updated_at":"2015-12-02T15:03:16Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/matplotlib/matplotlib/pulls/5603","html_url":"https://github.com/matplotlib/matplotlib/pull/5603","diff_url":"https://github.com/matplotlib/matplotlib/pull/5603.diff","patch_url":"https://github.com/matplotlib/matplotlib/pull/5603.patch"},"body":"When the snapping of circle markers was disabled in 37927b2, in order to make them look more round, it also made them half a pixel off of center (since the snapping was no longer happening).  This shifts non-snapped markers by half a pixel to keep (0, 0) running down the middle of the pixel.\r\n\r\nBEFORE THIS PR:\r\n\r\n![old](https://cloud.githubusercontent.com/assets/38294/11532448/d7794d1a-98d1-11e5-80ca-a6e76246c555.png)\r\n\r\nAFTER THIS PR:\r\n\r\n![new](https://cloud.githubusercontent.com/assets/38294/11532456/e17c1e8c-98d1-11e5-8025-a54013a0c903.png)\r\n\r\nAs a procedural point, we should try to get this in before #5307, as it will change many of the baseline images (for the better, we hope)."},"comment":{"url":"https://api.github.com/repos/matplotlib/matplotlib/issues/comments/161325379","html_url":"https://github.com/matplotlib/matplotlib/pull/5603#issuecomment-161325379","issue_url":"https://api.github.com/repos/matplotlib/matplotlib/issues/5603","id":161325379,"user":{"login":"mdboom","id":38294,"avatar_url":"https://avatars.githubusercontent.com/u/38294?v=3","gravatar_id":"","url":"https://api.github.com/users/mdboom","html_url":"https://github.com/mdboom","followers_url":"https://api.github.com/users/mdboom/followers","following_url":"https://api.github.com/users/mdboom/following{/other_user}","gists_url":"https://api.github.com/users/mdboom/gists{/gist_id}","starred_url":"https://api.github.com/users/mdboom/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mdboom/subscriptions","organizations_url":"https://api.github.com/users/mdboom/orgs","repos_url":"https://api.github.com/users/mdboom/repos","events_url":"https://api.github.com/users/mdboom/events{/privacy}","received_events_url":"https://api.github.com/users/mdboom/received_events","type":"User","site_admin":false},"created_at":"2015-12-02T15:03:15Z","updated_at":"2015-12-02T15:03:15Z","body":"> And when we lower the tolerance to zero, and images are remade en masse, are we going to be able to verify every single marker is drawn correctly?\r\n\r\nYes.  That was why I built the comparison tool in #5521, to make that kind of thing *much* easier.\r\n\r\n> Also, we don't have all that many tests that use different resolutions?\r\n\r\nThat's true.\r\n\r\n> I would love to see test images made at fairly low resolutions that draws lines like you have above and plots markers at their intersections. Having it at a low resolution would make it visually obvious that something is wrong.\r\n\r\nThat's a good point."}}