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Bottom of canvas disappears when the page scroll hits top

1601333458

Edited 1601333498
Zedafty
Pro
Sheet Author
Hello everybody ! Found something weird about the Roll20 canvas. The below has been tested under updated Brave and Firefox. When the canvas display size (altered by zoom level) is strictly lower than screen height + margin, no issue. When the canvas display size is greater than the screen height, no issue. BUT When the canvas display size is between screen height + margin then the top value is wrong somewhat and result in a glitch ... On screenshots below, for a screen of 1920x1280 and a map size of 700x700 (tiles doubled). If zoom is lower than 110%, no issue. If zoom is greater than 140%, no issue. BUT If zoom is between 110% and 140%, then the bottom of canvas disappears (appears like a wrong top value, in fact the canvas content seems to be translated to the top a little too much). Hope that someone could understand what I tried to report, thank you for reading :P
Probably related to this reported bug?: <a href="https://app.roll20.net/forum/post/8455731/canvas-scrolling-bug-with-likely-cause-in-code" rel="nofollow">https://app.roll20.net/forum/post/8455731/canvas-scrolling-bug-with-likely-cause-in-code</a>
1601336794
Zedafty
Pro
Sheet Author
Oh ! Definitively, thank you :P
1601338898
keithcurtis
Forum Champion
Marketplace Creator
API Scripter
Yeah, that's been true forever.
1601347542
Zedafty
Pro
Sheet Author
Until issue is fixed ! Hope this will happen one day :P
1601362076
Gold
Forum Champion
Make a larger Page Size (much larger). Put your content in the middle. Leave margins on the sides, within the page content. Colorize those margins as you like by setting the Page Background Color (or hide them with basic regular Fog Of War as all-black to players, token-working area for the GM). This works around the problem mentioned, side benefit it looks nicer &amp; gives the user better accessibility for range of zoom and dimmer background contrast.
1601392748
keithcurtis
Forum Champion
Marketplace Creator
API Scripter
I do this with most smaller maps. I also hide the margins with regular fog of war. It makes a great place to tuck reinforcements, or portraits and images you want to preview for the characters with a Shift-Z zoom.
I really wish they would fix this!&nbsp; It really annoys me!
1601400065
Brian C.
Pro
Marketplace Creator
Compendium Curator
The thing you have to be careful about with the Fog of War border is that if you are also running Advanced Fog of War and need to reset, suddenly your entire map is covered by regular fog of war.
1601440477
Gold
Forum Champion
Advanced Fog has not interacted nicely with my large-page-size technique. Not just the reset that Brian mentioned, but mainly, the larger the page = more lag from DL especially UDL. However a page with regular normal Fog Of War, can far-exceed the Roll20 default warning message for Page size. (The warning starts at 50x50, but one can run beyond 190x190, with AFoW turned OFF).
Has there been any word of this being adressed/fixed anytime soon? As I understand it was forwarded to the dev team more than five months ago?
1601572507
keithcurtis
Forum Champion
Marketplace Creator
API Scripter
I believe that it is part of the migration from Canvas to WebGL, which is not yet finished. That's my understanding, anyway.
1602366941

Edited 1602371893
I have actually traced this down to the function causing it. When the scaling is not at 100% and the top or left of the canvas goes into the negative numbers, the&nbsp;calculateScrollsContainerMeasurementsFrom in app.js returns the wrong value. It always returns the min value of editorHeight - paddingOffsetHeight - (smaller of those) or the pageHeight. I have tested the following function changes on my system and they seem to work: &nbsp;hope this helps to fix this issue! EDIT: I actually found that the 'e.scale &lt; 1' check is not needed. Even at 100% this issue can occur.