Android Question Canvas - Pinch & Zoom and adding images

[Pravin Shah]

Hi All,

I am using a Canvas object to draw chart on it. The chart is drawn using rectangle and lines. The chart is large in size and can't be fit in one screen so I would like to give a facility to user to zoom in / out of the chart. I understood that pinch and zoom can be used to provide this option. I have attached the image of the chart with the thread for reference.

So I have some questions -

1. How can I add the Pinch & Zoom functionality to this canvas so that app users can zoom in and out of the chart.

2. I also want to add images to the chart rectangles so that it occupies the rectangle (refer to attached chart), I am not sure how to do that. Also when the user zoom in or zoom out, these images should also become small or big proportionately.

3. Also I would like to capture the click event of these images and run some code.

Appreciate you help. thanks in advance.

 

[Pravin Shah]

I got following code for attaching images to the rect on canvas so this will be certainly useful. Now waiting for how to add zoom functionality

Sub Globals
    Dim cvsActivity As Canvas
End Sub

Sub Activity_Create(FirstTime As Boolean)
    cvsActivity.Initialize(Activity)
End Sub

Sub Activity_Resume
    Dim i As Int
    Dim r As Rect
    Dim imgW, imgH, x, y As Int
   
    imgW = 50%x
    imgH = imgW / 3 * 2        ' image ratio W/H = 3/2
    For i = 0 To 3
        x = (i Mod 2) * imgW
        y = Floor(i / 2) * imgH
        r.Initialize(x, y, x + imgW, y + imgH)
        cvsActivity.DrawBitmap(LoadBitmap(File.DirAssets, "image" & i & ".jpg"), Null, r)
    Next
End Sub

 

[johndb]

I would suggest that you review the Pinch and Zoom tutorial and adapt the process to your application?

 

[Pravin Shah]

Thanks @johndb.. I will have a look at the tutorial and see how it can be implemented..

 

[Informatix]

I would suggest that you review the Pinch and Zoom tutorial and adapt the process to your application?

A good and useful class but not a tutorial at all. It should be moved in the Additional libraries and classes section.