How to scroll the workspace from code correctly

[phil cleaver]

I am having problems finding the correct way to scroll the workspace from code.

What I do at the moment is

Blockly.mainWorkspace.scrollX = Blockly.mainWorkspace.scrollX - desiredScrollX;

Blockly.mainWorkspace.scrollY = Blockly.mainWorkspace.scrollY - desiredScrollY;

Blockly.mainWorkspace.render();

It works, but if the workspace has lots of blocks it's really slow, even when using requestAnimationFrame.

Any help appreciated.

Phil

[Mark Friedman]

I think that ScrollbarPair.set() in scrollbar.js might be what you're looking for.  You could call it with something like Blockly.mainWorkspace.scrollbar.set(x, y).

-Mark

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[phil cleaver]

Thanks a million marks, it works brilliantly

 :)

[phil cleaver]

Mark, 

Thanks for your help.  This method does indeed set the scrollbars and scroll the workspace, but I'm having difficulty finding the correct value to set them to.

If I set them to 0,0, I see the top left of the workspace, similarly if I set them to (contentwidth, contentheight), i see bottom right.  This is great for setting them to an absolute position, but I'm trying to get them to "scroll" in a relative way.

I'm having problems finding the currentPosition of scrollbars so I can add / subtract values for scrolling?

This also needs to work under different window zooming levels.

Thanks 

On Thursday, March 27, 2014 1:34:27 AM UTC+7, Mark Friedman wrote:

[phil cleaver]

to answer my own question, in case anyone else was wondering, this seems to work:

function scrollRelative(xAmount, yAmount) {

var metrics = Blockly.mainWorkspace.getMetrics();

var currentScrollX = (metrics.viewLeft - metrics.contentLeft );

var currentScrollY = (metrics.viewTop - metrics.contentTop );

Blockly.mainWorkspace.scrollbar.set(currentScrollX + xAmount, currentScrollY + yAmount);

[Austin Bart]

Anyone know how to scroll the view to the center? I was hoping that 

var newScrollX = (metrics.contentWidth - metrics.viewWidth ) / 2;

var newScrollY = (metrics.contentHeight - metrics.viewHeight ) / 2;

Blockly.mainWorkspace.scrollbar.set(newScrollX, newScrollY);

Would work, but I'm clearly missing something else. Any ideas?

[Eric Miller]

Try 

Blockly.mainWorkspace.scrollX = ...;

Blockly.mainWorkspace.scrollY = ...;

Blockly.mainWorkspace.render();

You want to update the workspace itself, not just the graphical scrollbars.