Selection is off when using nyaovim-tree-view

[city41]

When using nyaovim-tree-view, the mouse selection algorithm of neovim-editor doesn't account for the width of the tree-view, causing the selection to be off.

Expected Behavior

When clicking in the editor, and dragging a selection, the text that was dragged over becomes selected

Actual Behavior

Text to the right of what was dragged over gets selected, how far right is dependent on how wide nyaovim-tree-view is

Steps to Reproduce (including precondition)

1. install nyaovim-tree-view plugin as its README shows
2. start nyaovim and edit a file
3. using the mouse, select a sentence

Screenshot on This Problem (if possible)

Notice how the mouse cursor is off to the left compared to the selected text

Your Environment

• OS: Debian 8.5
• NyaoVim version:

NyaoVim version 0.0.20
  electron : 1.3.4
  chrome : 52.0.2743.82
  node : 6.3.0
  v8 : 5.2.361.43

• nvim version: 0.1.5
• Keyboard layout: US ANSI Qwertry
• Linux: Window manager: i3

Additional Comments (if any)

I was able to fix this bug by patching ScreenDrag.

I changed this:

    ScreenDrag.prototype.getPos = function (e) {
        return [
            Math.floor(e.clientY / this.store.font_attr.height),
            Math.floor(e.clientX / this.store.font_attr.width),
        ];
    };

To this:

    ScreenDrag.prototype._getRelCoord = function(e, container) {
        var pos = {}, offset = {}, ref;

        ref = container.offsetParent;

        pos.x = e.clientX;
        pos.y = e.clientY;

        offset.left = container.offsetLeft;
        offset.top = container.offsetTop;

        while ( ref ) {

            offset.left += ref.offsetLeft;
            offset.top += ref.offsetTop;

            ref = ref.offsetParent;
        }

        return { 
            x : pos.x - offset.left,
            y : pos.y - offset.top,
        }; 

    };
    ScreenDrag.prototype.getPos = function (e) {
        const target = document.querySelector('.neovim-canvas');
        const relCoords = this._getRelCoord(e, target);
        return [
            Math.floor(relCoords.y / this.store.font_attr.height),
            Math.floor(relCoords.x / this.store.font_attr.width),
        ];
    };

[rhysd]

Thank you for catching this bug. I could confirm 😄