Zooming in on a specific part of the canvas from a script

[thkwznk]

This is purely a feature request, ot seems that there's no working option to zoom in on a specific part of a canvas using the Lua API.

The Zoom command doesn't allow for specifing a point to zoom to (or from) other then the center. And the app.useTool method for the zoom tool produces no results (in the v1.3.9-2).

[thkwznk]

I actually found a solution to my own problem, it was a combination of a zoom and scroll. Here's a sample function that can scroll to a slice with a little heuristic for calculating an appropriate zoom:

function ScrollToSlice(slice, autoZoom)
    -- Center the canvas first
    app.command.ScrollCenter()

    local sliceCenterX = slice.bounds.x + slice.bounds.width / 2
    local sliceCenterY = slice.bounds.y + slice.bounds.height / 2

    local centerX = slice.sprite.width / 2
    local centerY = slice.sprite.height / 2

    if sliceCenterX < centerX then
        app.command.Scroll {
            direction = "left",
            units = "zoomed-pixel",
            quantity = tostring(centerX - sliceCenterX)
        }
    else
        app.command.Scroll {
            direction = "right",
            units = "zoomed-pixel",
            quantity = tostring(sliceCenterX - centerX)
        }
    end

    if sliceCenterY < centerY then
        app.command.Scroll {
            direction = "up",
            units = "zoomed-pixel",
            quantity = tostring(centerY - sliceCenterY)
        }
    else
        app.command.Scroll {
            direction = "down",
            units = "zoomed-pixel",
            quantity = tostring(sliceCenterY - centerY)
        }
    end

    if autoZoom then
        local sizes = {
            64, 48, 32, 24, 16, 12, 8, 6, 5, 4, 3, 2, 1, 0.5, 0.333, 0.25, 0.20,
            0.167, 0.125 -- There are a few skipped zoom options
        }

        for _, size in ipairs(sizes) do
            -- The window width and height percentages are just heuristic values to make the zoom not bee too harsh
            if slice.bounds.width * size < app.window.width * 0.8 and
                slice.bounds.height * size < app.window.height * 0.6 then
                app.command.Zoom {
                    percentage = tostring(size * 100),
                    focus = "center"
                }
                break
            end
        end
    end
end

[dacap]

@thkwznk we'll add app.editor.zoom and app.editor.scroll properties, but I'm not sure if they will be enough for your case. The zoom property will be a number (floating-point number), and the scroll a table (not a Point) with two x and y fields (floating-point numbers), which will indicate the specific sprite pixel that is showing the center of the editor. We'll be able to get/set these properties.

[thkwznk]

@dacap It should be more than enough, just knowing the zoom value will allow for restoting zoom after moving the view.