How to save an image from QML Image element?

[DonRico]

Hi

Does anybody have an idea why I can't pass the Image object to the save function. The path comes over nicely but "imageObj" pointer in save() function turns out empty?

[qomg]

Hi

I also have an empty pointer. I do not know where to look to solve this problem.

[jeremy_k]

For Qt 5 and later, "Canvas":http://qt-project.org/doc/qt-5/qml-qtquick-canvas.html has loadImage(url) and save(filename) functions.

[Vincent007]

wait for QQuickRenderControl

[qomg]

I tried to use the Canvas, and also I could not save.
I'll try again tomorrow ..

[jeremy_k]

Image loading and saving via Canvas:

@import QtQuick 2.2
import QtQuick.Window 2.1

Window {
width: imgLoader.sourceSize.width
height: imgLoader.sourceSize.height
visible: true
property string loadUrl: "file://tmp/image.png"
property string saveUrl: "/tmp/i2.png"

Canvas {
    id: root
    anchors.fill: parent
    onPaint: {
        var ctx = getContext("2d")
        ctx.drawImage(imgLoader, 0, 0)
    }
}
MouseArea {
    anchors.fill: parent
    onClicked: {
        if (root.save(saveUrl)) {
            console.log("save succeeded")
        }
        else {
            console.log("save failed")
        }
    }
}
Image {
    id: imgLoader
    visible: false
    source: loadUrl
}

}@

Note that the parameter to Canvas::save() is a filename, not a URL. It fails when "file://tmp/i2.png" is used.

[qomg]

jeremy_k thanks it works great.

[beemaneni]

Hi
does the above code really draw an image in the given path?
For me the file gets created but nothing in it... i have given save url as "/storage/sdcard0/a1.png".

Can u help me ?

Thanks in Advance,,

[DonRico]

Hi

I decided to solve this a bit differently. I created a new QML type (c++ class) that takes in image url (local or remote) and spits out local url. In case of beginning http:// or https:// class checks if image is already downloaded from the remote server and in that case spits the local url right out w/o wasting the precious mobile data bandwidth.And then there a QML component that fills out the Image type source property when the local url is returned from my so called "Caching class". If anybody's interest I can strip it out of my project and put it up to github with decent comments.

[beemaneni]

Hi DonRico
If u can post that code that would be an great help for me...can u?

Thanks

[DonRico]

Ok, I'll try to find some spare time to separate it and put it.

[DonRico]

Ok, the exmaple project is available in https://github.com/DonRico/QT-Image-Caching . There might be some issues since I've written QT for 2mos for now but it should give you the general idea.

[jeremy_k]

Caching can also be handled with a "QQuickImageProvider":https://qt-project.org/doc/qt-5/qquickimageprovider.htmlQQuickImageProvider.

After defining and register a provider, image urls can be written as "image://ProviderName/path/to/image".

The same concept exists for Qt 4 in the form of QDeclarativeImageProvider.

[chuahanmandis]

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