Un-tilt && scale 1:1 && big image

[zvezdochiot]

On large images (http://papacoma.narod.ru/maps/maps-images2/agdm_18615_b.jpg) in 1: 1 mode, when using Un-tilt and based on it, there are hard glitches: twitching and disappearing of the image from the canvas. It is impossible to work. Observed on both my Un-tilt implementation and implementation @ksharindam .

[ksharindam]

normal crop function should have the same problem. Because, the large pixmap is copied and drawn over it. may be drawing the rectangle on large pixmap is slow, or setting the pixmap is slow. Have to test it.

In both cases there is no simple solution.

[zvezdochiot]

❓ Maybe you should move drawCropBox(); in onMouseRelease?

[zvezdochiot]

It was possible to achieve performance by replacing interactivity with a pure click:

void
PerspectiveTransform:: onMousePress(QPoint pos)
{
    int i, n;
    float dx, dy, r, rmin = 0.0f;
    clk_pos = pos;
    clk_area = 0;
    n = pt.count();
    for (i = 0; i < n; i++)
    {
        dx = clk_pos.x() - pt[i].x();
        dy = clk_pos.y() - pt[i].y();
        r = dx * dx + dy * dy;
        if ((i == 0) || (r < rmin))
        {
            clk_area = i + 1;
            rmin = r;
        }
    }
    QPointF last_pt = QPoint(pixmap.width()-1, pixmap.height()-1);
    QPointF new_pt;
    if (clk_area > 0)
    {
        new_pt = pos;
        p[clk_area - 1] = QPointF(MIN(last_pt.x(), MAX(0, new_pt.x())), MIN(last_pt.y(), MAX(0, new_pt.y())));
    }
    pt = p;
}

void
PerspectiveTransform:: onMouseRelease(QPoint /*pos*/)
{
    drawCropBox();
}

⚠️ The bug with the disappearance of the image from the canvas remains!

[ksharindam]

Working with very large images require large memory. How much ram do your pc have?

Absence of interactive nature is undesirable. Interactivity should be disabled only in larger images.

On Sun, 8 Aug, 2021, 10:00 PM звездочёт, @.***> wrote:

It was possible to achieve performance by replacing interactivity with a pure click:

void

PerspectiveTransform:: onMousePress(QPoint pos)

{

int i, n;

float dx, dy, r, rmin = 0.0f;

clk_pos = pos;

clk_area = 0;

n = pt.count();

for (i = 0; i < n; i++)

{

    dx = clk_pos.x() - pt[i].x();

    dy = clk_pos.y() - pt[i].y();

    r = dx * dx + dy * dy;

    if ((i == 0) || (r < rmin))

    {

        clk_area = i + 1;

        rmin = r;

    }

}

QPointF last_pt = QPoint(pixmap.width()-1, pixmap.height()-1);

QPointF new_pt;

if (clk_area > 0)

{

    new_pt = pos;

    p[clk_area - 1] = QPointF(MIN(last_pt.x(), MAX(0, new_pt.x())), MIN(last_pt.y(), MAX(0, new_pt.y())));

}

pt = p;

drawCropBox();

}

⚠️ The bug with the disappearance of the image from the canvas remains!

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[zvezdochiot]

ℹ️ RAM: 8.00 Gb

Interactivity should be disabled only in larger images.

No. The bug does not occur if the large image is scaled to fit the window. The bug is related to scrolling.

[zvezdochiot]

https://github.com/ImageProcessing-ElectronicPublications/photoquick/blob/2bbafe0cb64368a4951518f2e868e1a890e22224/src/transform.cpp#L324 https://github.com/ImageProcessing-ElectronicPublications/photoquick/blob/2bbafe0cb64368a4951518f2e868e1a890e22224/src/transform.cpp#L399-L400 in 1: 1 mode, it triples memory consumption.

[zvezdochiot]

Hi @ksharindam .

❓ Maybe add a selection dialog box to reduce memory consumption: color / quant / BW (threshold)?