Qimagereader and cliprect example

[BinuJanardhanan]

I am developing an image viewer to load and show high-resolution image. I am planning to use Qimagereader and cliprect function.
Anybody please help me to know how to map the region of interest coordinate maping to high resolution image.
That means how can i use cliprect function ?

[mrjj]

Hi
I have not seem any examples so i made you one.

#include <QImageReader>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QImageReader reader("e:/test.jpg");
    reader.setClipRect(QRect(100, 100, 100, 100));
    QImage img;
    if ( reader.canRead()) {
        img = reader.read();
        ui->label->setPixmap(QPixmap::fromImage(img)); // test show it
    } else
        qDebug() << "cannot read image";

that will load and draw 100,100, to 200,200 from the test image

and result is

and seems to check out in photoshop

I didnt have any real satelite images to test with.

[BinuJanardhanan]

@mrjj Thank you.

I am looking for one more example. i e i am having a scaled image of an actual high resoultion image and that showing it in the application first.And i select a portion of the scaled image as region of interset via a rectangle draw and then i collect the region interest coorinates. Now i want to load that region of interest area from the actual high resolution image to the another widget of the application. So my question is how can i map the coordinates from the scaled image to actual high resolution image. ?

[jsulm]

@BinuJanardhanan You ask exact same question in another thread!
Please do not duplicate your questions!

[BinuJanardhanan]

@jsulm sorry for that.
I put that question as a reply to the answer , i thought so he can easly identify my doubt. that why..

[mrjj]

Hi
. So my question is how can i map the coordinates from the scaled image to actual high resolution image. ?

well, you have to calculate the other way of what you did to make it "scaled".

[BinuJanardhanan]

@mrjj thanks.