Makie render function not called

[Daniel Vedder]

I'm struggling getting the Makie integration to work. Although I can run the two examples (makie.jl and makie-plot.jl) just fine, my own code only gives me a blank window:

using CxxWrap
using Observables
using QML
using GLMakie
using FileIO
using Persefone

ENV["QSG_RENDER_LOOP"] = "basic"
QML.setGraphicsApi(QML.OpenGL)

global model = initialise()

function render_map(screen)
    global model
    println("Updating map")
    figure = visualisemap(model)
    display(screen, figure.scene)
end

qmlfile = joinpath(dirname(@__FILE__), "mwe.qml")
loadqml(qmlfile,
        render_map_callback = @safe_cfunction(render_map,Cvoid,(Any,)))
println("Launched MWE.")
exec()

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
import org.julialang

ApplicationWindow {
	id: makieWindow
	title: "Makie integration"
	width: 1024
	height: 768
	visible: true

	MakieViewport {
		id: mapviewport
		Layout.fillWidth: true
		Layout.fillHeight: true
		renderFunction: render_map_callback
		
		Component.onCompleted: {
			mapviewport.update()
		}

	}

}

visualisemap() is a function that returns a Makie figure; if I call this directly, GLMakie plots it as expected.

My output shows no errors, simply an empty window. As I do not see the "Updating map" debug statement printed, I assume the render function is never called.

I'm using the main branch of QML.jl, GLMakie 0.6.13 and Makie 0.17.13

[Bart Janssens]

The problem here is with the QML, in the makie example we use a ColumnLayout, hence the Layout. options make sense there. Without a layout, you should use the anchors:

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
import org.julialang

ApplicationWindow {
	id: makieWindow
	title: "Makie integration"
	width: 1024
	height: 768
	visible: true

	MakieViewport {
		id: mapviewport
		anchors.fill: parent
		renderFunction: render_map_callback
	}

}

Ref: https://doc.qt.io/qt-6.5/qtquick-positioning-anchors.html

[Daniel Vedder]

Ah, that was it! I had eventually figured out that it must be something to do with layouts, but didn't know enough to understand what. Thanks for the pointer!