support for scrollbars that are not full client size - proposition

[flexphperia]

Now plugin does not support scrollbar width/height that is smaller than clientWidth/clientHeight.

Replace _mouseMoveDocumentHandler method with this:

GeminiScrollbar.prototype._mouseMoveDocumentHandler = function(e) {
    if (this._cursorDown === false) {
        return;
    }

    var offset, thumbClickPosition, thumbPositionPercentage; 

    if (this._prevPageY) {
        offset = ((this._scrollbarVerticalElement.getBoundingClientRect().top - e.clientY) * -1);
        thumbClickPosition = (this._thumbVerticalElement.offsetHeight - this._prevPageY);
        thumbPositionPercentage = ((offset - thumbClickPosition) * 100 / this._scrollbarVerticalElement.offsetHeight); //CHANGE

        this._viewElement.scrollTop = (thumbPositionPercentage * this._viewElement.scrollHeight / 100);

        return;
    }

    if (this._prevPageX) {
        offset = ((this._scrollbarHorizontalElement.getBoundingClientRect().left - e.clientX) * -1); 
        thumbClickPosition = (this._thumbHorizontalElement.offsetWidth - this._prevPageX);
        thumbPositionPercentage = ((offset - thumbClickPosition) * 100 / this._scrollbarHorizontalElement.offsetWidth); //CHANGE

        this._viewElement.scrollLeft = (thumbPositionPercentage * this._viewElement.scrollWidth / 100);
    }
};

[flexphperia]

noeldelgado, can you review this change?
It works fine, but sometimes (on different scroll sizes) thumb do not touch end border of scrollbar when scrolled to end.

EDIT: this happens only on Chrome - possible cause: rounding method of css values

[noeldelgado]

You are right, I just tried and I can confirm. This also happens if you put some offsets for the gm-scrollbar -vertical and/or gm-scrollbar -horizonta elements. e.g. top: 20px; bottom: 20px.

I also found that the _clickVerticalTrackHandler and _clickHorizontalTrackHandler methods will need to be fixed as well.

Changing

var thumbPositionPercentage = ((offset - thumbHalf) * 100 / this._viewElement.clientHeight);
// to
var thumbPositionPercentage = ((offset - thumbHalf) * 100 / this._scrollbarVerticalElement.offsetHeight);

and

var thumbPositionPercentage = ((offset - thumbHalf) * 100 / this._viewElement.clientWidth);
// to
var thumbPositionPercentage = ((offset - thumbHalf) * 100 / this._scrollbarHorizontalElement.offsetWidth);

Do you want to do the PR? otherwise I can take it.

thanks!

[flexphperia]

Thanks. Sorry I dont know what is "PR" so better you do it :)

[noeldelgado]

PR = Pull Request

How you ever going into the process of forking and contributing to a project before?

If you want to do it I am more than happy to assist you in any way I can.

If you do not feel like doing it right now, no problem, I just think it could be a good chance in case you haven't done it before :)

[flexphperia]

Thanks but I'm only commenting and submiting bugs. I'm fine with this for now. I have own something like repository when I collect plugins with changes made by me :)

[noeldelgado]

Ok, cool 👍