Support anchor in pixels about excalibur HOT 5 OPEN

@mattjennings I agree! I think a pixel offset is useful in this case. Let me play around with the first one, a ex.Anchor type that extends vector would be a relatively easy drop in.

We do have a way to do this (but not super visible on actor). On the graphics component we have a actor.graphics.offset property that will shift graphics by pixels.

const actor = new ex.Actor({...});
actor.graphics.anchor = ex.vec(0, 0); // zero out the anchor
actor.graphics.offset = ex.vec(-8, -8); // offset 

Internally this is the drawing code in GraphicsSystem

    let anchor = graphicsComponent.anchor;
    let offset = graphicsComponent.offset;

    // handle specific overrides
    if (options?.anchor) {
      anchor = options.anchor;
    }
    if (options?.offset) {
      offset = options.offset;
    }
    // See https://github.com/excaliburjs/Excalibur/pull/619 for discussion on this formula
    const offsetX = -graphic.width * anchor.x + offset.x;
    const offsetY = -graphic.height * anchor.y + offset.y;

    const oldFlipHorizontal = graphic.flipHorizontal;
    const oldFlipVertical = graphic.flipVertical;
    if (flipHorizontal || flipVertical) {
      // flip any currently flipped graphics
      graphic.flipHorizontal = flipHorizontal ? !oldFlipHorizontal : oldFlipHorizontal;
      graphic.flipVertical = flipVertical ? !oldFlipVertical : oldFlipVertical;
    }

    graphic?.draw(
      this._graphicsContext,
      offsetX,
      offsetY);

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We could also expose offset in the actor constructor?

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I actually did try using the offset on the graphics initially (and I do think it's worth exposing that on the actor constructor), but it wasn't quite the same thing as adjusting the anchor. For example, when I applied a scale it still scaled according to the anchor point. I suppose the scale effect could account for this, but I think that's more a symptom of the issue.

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Good points, also it should totally account for the scale that's definitely a bug

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This issue hasn't had any recent activity lately and is being marked as stale automatically.

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