How to scroll axis scale outside the graph of Zedgraph using the mouse event

Question

Is it possible that the axis scale outside the graph could be scale using the mouse event "mouse_down and hold" and move up or down in y-axis the same with the x-axis move left or right? ex. when I trigger MouseDownEvent and hold the x-axis scale 0.6 or at the space along with that scale and move it to the right, scale should scroll depend in the chartfraction? could you post an example? Thanks in advance!

score 1 · Answer 1 · answered Nov 15 '13 at 19:34

Separately panning and zooming Y axises can be achieved using the mouse events of ZedGraph: MouseDownEvent, MouseMoveEvent, MouseUpEvent and MouseWheel events (credits go to a colleague of mine).

It works with multiple GraphPanes and multiple Y axises.

The MouseMoveEvent is used to shift the Min and the Max of an Y axis when the mouse is moved while its button is pressed. If not, it is used to get the reference of the Y axis object the mouse is hovering on.

The MouseDownEvent is used to initiate an axis pan operation.

The MouseWheel is used to perform a zoom on an Y axis.

And the MouseUpEvent is used to clean things when zooming and panning operations are finished.

Here is the code :

// The axis that is currently hovered by the mouse
YAxis hoveredYAxis;

// The graphpane that contains the axis
GraphPane foundPane;

// The scale of the axis before it is panned
double movedYAxisMin;
double movedYAxisMax;

// The Y on the axis when the panning operation is starting
float movedYAxisStartY;

void z_MouseWheel(object sender, MouseEventArgs e)
{
    if (hoveredYAxis != null)
    {
        var direction = e.Delta < 1 ? -.05f : .05f;
        var increment = direction * (hoveredYAxis.Scale.Max - hoveredYAxis.Scale.Min);
        var newMin = hoveredYAxis.Scale.Min + increment;
        var newMax = hoveredYAxis.Scale.Max - increment;

        hoveredYAxis.Scale.Min = newMin;
        hoveredYAxis.Scale.Max = newMax;

        foundPane.AxisChange();

        z.Invalidate();
    }
}

bool z_MouseUpEvent(ZedGraphControl sender, MouseEventArgs e)
{
    hoveredYAxis = null;
    return false;
}

bool z_MouseMoveEvent(ZedGraphControl sender, MouseEventArgs e)
{
    var pt = e.Location;

    if (e.Button == System.Windows.Forms.MouseButtons.Left)
    {
        if (hoveredYAxis != null)
        {
            var yOffset = hoveredYAxis.Scale.ReverseTransform(pt.Y) - hoveredYAxis.Scale.ReverseTransform(movedYAxisStartY);
            hoveredYAxis.Scale.Min = movedYAxisMin - yOffset;
            hoveredYAxis.Scale.Max = movedYAxisMax - yOffset;

            sender.Invalidate();
            return true;
        }
    }
    else
    {
        var foundObject = findZedGraphObject(null);
        hoveredYAxis = foundObject as YAxis;

        if (hoveredYAxis != null)
        {
            z.Cursor = Cursors.SizeNS;
            return true;
        }
        else
        {
            if (z.IsShowPointValues)
            {
                z.Cursor = Cursors.Cross;
                return false;
            }
            else
            {
                z.Cursor = Cursors.Default;
                return true;
            }
        }
    }

    return false;
}

bool z_MouseDownEvent(ZedGraphControl sender, MouseEventArgs e)
{
    if (e.Button == System.Windows.Forms.MouseButtons.Left)
    {
        if (hoveredYAxis != null)
        {
            movedYAxisStartY = e.Location.Y;
            movedYAxisMin = hoveredYAxis.Scale.Min;
            movedYAxisMax = hoveredYAxis.Scale.Max;
            return true;
        }
    }

    return false;
}

This is a helper that factorizes a bit the object find operations of ZedGraph.

object findZedGraphObject(GraphPane pane = null)
{
    var pt = zgc.PointToClient(Control.MousePosition);

    if (pane == null)
    {
        foundPane = zgc.MasterPane.FindPane(pt);
        if (foundPane != null)
        {
            object foundObject;
            int forget;

            using (var g = zgc.CreateGraphics())
                if (foundPane.FindNearestObject(pt, g, out foundObject, out forget))
                    return foundObject;
        }
    }

    return null;
}

I used this, with a little modification, to scale the y-axis by sliding the y-axis itself. Thank you! — Luminous, Nov 04 '14 at 16:48
Oh my, this is old stuff. I will post an update as soon time allows it. Glas it helped! — Larry, Nov 04 '14 at 18:55

score 0 · Answer 2 · answered Sep 07 '12 at 16:49

0

If I understand your question correctly, here's my response:

zedgraph has got an in-built function called "Pan", you could change the scale of x & y axis.

Place the cursor within the 'chart area' Hold the 'ctrl' button & move the mouse towards x & y directions to change the scale.

you could get back to original state by 'Un-Pan' (Context Menu)

Cheers..:)

answered Sep 07 '12 at 16:49

SanVEE

2,009
5
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San, I understand what you are saying but what I really want is to make that function "outside the chart area" not with in the chart. For ex. I have x-axis scale 0.0 0.1 0.2 0.3. I want to click and hold the scale label 0.1 and move the mouse towards left and at the same time it should re-scale into 0.1 0.2 0.3 0.4. – Cold Sep 08 '12 at 12:22

score 0 · Answer 3 · answered Oct 01 '12 at 12:46

0

Do You want to create a ScrollBar?

 zedGraphControl1.IsShowHScrollbar = true;
//Set borders for the scale
zedGraphControl1.GraphPane.XAxis.Scale.Max = Xmax;
zedGraphControl1.GraphPane.XAxis.Scale.Min = Xmin;

answered Oct 01 '12 at 12:46

Pablo Elias

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How to scroll axis scale outside the graph of Zedgraph using the mouse event

3 Answers3