QML - GridLayout - ROW and COLUMN Span - Understanding

Vildnex · wrote on 14 May 2020, 17:32

I'm trying to learn QML and at this moment I'm having some problems with understanding of rowSpan and columnSpan, so sorry if this question may sound stupid for some of you.

WHAT I LEARNED:

Correct me if I'm wrong but in a GridLayout should be like this:

Layout.row - indicates the line where the object is located;
Layout.column - indicates the column in which the object is located;
Layout.rowSpan - indicates how many lines should be stretched object;
Layout.columnSpan - indicates how many columns should be stretched
object;

WHAT I'M TRYING TO DO:

Well, in this case, I'm trying to recreate this layout over here

This layout, in theory, should have the followings:

The actual GridLayout should be composed out of 24 columns and 9 rows
RED shape should be at -> col 0, row 1 -> colSpan 3, rowSpan 7
BLUE shape should be at -> col 3, row 1 -> colSpan 8, rowSpan 1
PURPLE shape should be at -> col 3, row 4 -> colSpan 6, rowSpan 3

Or at least that's what I've understood so far.

THE PROBLEM:

After I've coded the QML with the col, row accordantly, and also colSpan and rowSpan I've obtained this instead.

MY CODE:

import QtQuick 2.5
import QtQuick.Controls 1.4
import QtQuick.Layouts 1.1

Item {
    width: 1366
    height: 512

    GridLayout {
        id: grid

        columns: 24
        rows: 9
        anchors.fill: parent

        Rectangle {

            property var rowSpan: 7
            property var columSpan: 3

            Layout.column: 0
            Layout.row: 1

            Layout.preferredWidth: (parent.width / parent.columns) * columSpan
            Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

            Layout.columnSpan: columSpan
            Layout.rowSpan: rowSpan

            color: "red"

        }

        Rectangle {
            property var rowSpan: 1
            property var columSpan: 8

            Layout.column: 3
            Layout.row: 1

            Layout.preferredWidth: (parent.width / parent.columns) * columSpan
            Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

            Layout.columnSpan: columSpan
            Layout.rowSpan: rowSpan

            color: "blue"
        }
        Rectangle {
            property var rowSpan: 3
            property var columSpan: 6

            Layout.column: 4
            Layout.row: 3

            Layout.preferredWidth: (parent.width / parent.columns) * columSpan
            Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

            Layout.columnSpan: columSpan
            Layout.rowSpan: rowSpan

            color: "purple"
        }
    }
}

Could anyone explain to me what I'm doing wrong or which part of GridLayout I didn't get it right?

fcarney · wrote on 14 May 2020, 19:27

I think its doing some autolayout on top of the row and column specifier. I don't quite understand why they even offer the ability to specify row and column as it does not work as I would expect.

import QtQuick 2.12
import QtQuick.Window 2.12

import QtQuick.Controls 1.5
import QtQuick.Layouts 1.12

Window {
    visible: true
    width: 1366
    height: 512
    title: qsTr("Grid Spans")

    Item {
        width: 1366
        height: 512

        GridLayout {
            id: grid

            columns: 24
            rows: 9
            anchors.fill: parent
            columnSpacing: 0
            rowSpacing: 0

            onWidthChanged: {
                console.log(grid.width, grid.height)
            }

            Rectangle {

                property var rowSpan: 1 //7
                property var columSpan: 1 //3

                //Layout.column: 0
                //Layout.row: 1

                Layout.preferredWidth: (parent.width / parent.columns) * columSpan
                Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

                Layout.columnSpan: columSpan
                Layout.rowSpan: rowSpan

                color: "red"

            }

            Rectangle {
                property var rowSpan: 1 //1
                property var columSpan: 1 //8

                //Layout.column: 3
                //Layout.row: 1

                Layout.preferredWidth: (parent.width / parent.columns) * columSpan
                Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

                Layout.columnSpan: columSpan
                Layout.rowSpan: rowSpan

                color: "blue"
            }
            Rectangle {
                property var rowSpan: 1 //3
                property var columSpan: 1 //6

                //Layout.column: 4
                //Layout.row: 3

                Layout.preferredWidth: (parent.width / parent.columns) * columSpan
                Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

                Layout.columnSpan: columSpan
                Layout.rowSpan: rowSpan

                color: "purple"
            }
        }

        GridLayout {
            id: gridlines

            columns: 24
            rows: 9
            anchors.fill: parent
            columnSpacing: 0
            rowSpacing: 0

            Repeater {
                model: gridlines.columns*gridlines.rows
                delegate: transrects
            }
            Component {
                id: transrects

                Rectangle {
                    width: gridlines.width/gridlines.columns
                    height: gridlines.height/gridlines.rows

                    color: "transparent"
                    border.width: 1
                    border.color: "grey"
                    opacity: 0.5
                }
            }
        }
    }

}

Edit:

import QtQuick 2.12
import QtQuick.Window 2.12

import QtQuick.Controls 1.5
import QtQuick.Layouts 1.12

Window {
    visible: true
    width: 1366
    height: 512
    title: qsTr("Grid Spans")

    Item {
        width: 1366
        height: 512

        GridLayout {
            id: grid

            columns: 24
            rows: 9
            anchors.fill: parent
            columnSpacing: 0
            rowSpacing: 0

            onWidthChanged: {
                console.log(grid.width, grid.height)
            }

            Rectangle {

                property var rowSpan: 1 //7
                property var columSpan: 1 //3

                Layout.column: 0
                Layout.row: 1

                Layout.preferredWidth: (parent.width / parent.columns) * columSpan
                Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

                Layout.columnSpan: columSpan
                Layout.rowSpan: rowSpan

                color: "red"

            }

            Rectangle {
                property var rowSpan: 1 //1
                property var columSpan: 1 //8

                Layout.column: 3
                Layout.row: 1

                Layout.preferredWidth: (parent.width / parent.columns) * columSpan
                Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

                Layout.columnSpan: columSpan
                Layout.rowSpan: rowSpan

                color: "blue"
            }
            Rectangle {
                property var rowSpan: 1 //3
                property var columSpan: 1 //6

                Layout.column: 4
                Layout.row: 3

                Layout.preferredWidth: (parent.width / parent.columns) * columSpan
                Layout.preferredHeight: (parent.height / parent.rows) * rowSpan

                Layout.columnSpan: columSpan
                Layout.rowSpan: rowSpan

                color: "purple"
            }
        }

        GridLayout {
            id: gridlines

            columns: 24
            rows: 9
            anchors.fill: parent
            columnSpacing: 0
            rowSpacing: 0

            Repeater {
                model: gridlines.columns*gridlines.rows
                delegate: transrects
            }
            Component {
                id: transrects

                Rectangle {
                    width: gridlines.width/gridlines.columns
                    height: gridlines.height/gridlines.rows

                    color: "transparent"
                    border.width: 1
                    border.color: "grey"
                    opacity: 0.5
                }
            }
        }
    }

}