Fabric.js: controls not considered when using perPixelTargetFind if cache canvas is available

[finom]

Version

2.4.5

Test Case

http://jsfiddle.net/Da7SP/3322/
The test case is quite complicated because I had to transpile the code via babel. But the idea is simple: I want to render custom controls (blue circles) by _renderControls outside of the object (red arrow) itself (at "transparent zone") and use perPixelTargetFind: true.

Information about environment

Chrome 71

Steps to reproduce

Try to use handles (blue circles). First try to mousedown an intersect of a handle and the red arrow. Then try to mousedown the handle outside of the arrow.

Expected Behavior

The handles should be included at "perPixelTargetFind" zone.

Actual Behavior

When a handle is moused down outside of the arrow area, the arrow becomes inactive. It worked fine at 2.0.0-rc.4 if I set padding: "any number more than handle radius" but doesn't work anymore at latest version. The gif above is made using the old version of fabricjs.

[asturur]

i ll take a look asap.
Do you know that simple round controls are anyway a feature of the lib and you do not need custom code for them?

[finom]

@asturur thank you!
No, I didn't know. How can I enable them 😊? Can't find any info. The only thing I could do is:

[asturur]

http://fabricjs.com/docs/fabric.Object.html#cornerStyle

start to look from here and here:

http://fabricjs.com/fabric-changelog-old ( scroll down to 1.6.2 )

Also here:

http://fabricjs.com/controls-customization

That does not mean your problem is solved, i wanted just to point out that writing code to render circle controls is not necessary.

Said so i could not dig in your fiddle since the transpiled code is too much.
You need to focus on the important part that is target Transparency + custom controls, reducing to the bone the features that are not part of the bug.

How you draw the arrow should not be a problem here, just use a line.

[finom]

@asturur thank you for the links. My goal isn't to change the styling of standard controls (with 9 handles), my goals is to make completely custom controls with 2 handles on both ends of the arrow (inherited from Line class).

I have simplified the snipped above by removing _render method, most of event handlers and other lines of code. I've left only one handle and one event listener (mousedown). See http://jsfiddle.net/Da7SP/3342/

The problem is when you mousedown a thing rendered by _renderControls, its related object loses itsactive state (if perPixelTargetFind is used). In other words if you render something by _renderControls fabricjs thinks of it as of "transparent" zone.

Let me know is that clearer now.

[asturur]

Yes, the problem was clear, i wonder how it happens since the standard controls are usable with perPixelTargetFind.

My comment and links about the circle controls is that while you probably need to rewrite the function that render borders and call the function that draw the single controls, the exact function that draw the controls should be fine

[asturur]

Ok, the control does not work because you set hasControls to false.
You need to draw handle the controls with fabric logic or it won't work.

An easier way to handle this would be:

• leave just the real controls ml and mr active.
• make so that at initialization time the line is mad horizontal and rotated to reach the requested points
• add an hanlder for the scale that will move the points rather than scaling.

[finom]

the control does not work because you set hasControls to false

I've set the option to true, but it doesn't work anyway. IMO that's another bug: if hasControls is false then _renderControls should not be called or at least its result should be invisible. It appears that hasControls is only handled at the original function. Does it make sense?

An easier way to handle this would be

That looks like a tricky hack... I'm thinking to move controls rendering to _render method depending on its active state or make it as you proposed "you probably need to rewrite the function that render borders and call the function that draw the single controls". I guess you meant drawBorders method?

_renderControls is a part of the official API. I think it should either be removed from the documentation or it should be possible to override it. IMO currently it looks like a private method with public documentation.

[asturur]

http://jsfiddle.net/Da7SP/3344/
This is an example how to handle it differently ( i did not write the code to move the point of the line around )

There is for sure a bug that stops you from making your code work, and that can you work around disabling objectCaching for your subclass. And the bug should be fixed somehow.

Then my comment about the code is more about the fact that just rendering controls where you want will not make the controls easily targetable in other situations, is also true that i did not read the full code of the first fiddle and i have no idea how other things are handled.

About the trick hack i feel like those are similar way to get to the same result. You should override the simpler functions or the one with which you are most comfortable with if there is more than an option.

There is a connection between oCoords and controls rendering and control radius, you should keep those things as much as working together as possible.

[finom]

@asturur thank you.

[asturur]

i m fixing the bug we surfaced, this may fix or not fix your use case, i have no idea.

[finom]

@asturur any news about an official release?

[asturur]

i think i ll go for this sunday now that the gradient export is in too.

[Hellowor1d]

Version

2.4.5

Test Case

http://jsfiddle.net/Da7SP/3322/

This is a wonderful drag effect about the arrowLine, wiil you please update it after asturur's method in http://jsfiddle.net/Da7SP/3344/ ?

[finom]

@Hellowor1d a company I work for is planning to open source an ambitious image editor (but not earlier than in a month). Line arrow class is going to be open sourced as well.

[Hellowor1d]

@Hellowor1d a company I work for is planning to open source an ambitious image editor (but not earlier than in a month). Line arrow class is going to be open sourced as well.

Hi~ , has been the ambitious image editor published? waiting for your good news

[finom]

@Hellowor1d not yet :(