bitmap and finger move

[derez]

1. How do I create a bitmap which is a copy of a rectangle from another bitmap ? there are 3 options to initialize but not that one.

2. How do I implement "mouse" move - identify the finger touch on the activity and get the x y while it moves ?

 

[Erel]

1. You should use the Canvas object to copy a rectangle from one bitmap to another.
2. Activity_Touch event.
Do the following steps:
1. Write Sub followed by space.
2. Press Tab.
3. Choose Activity - Touch

 

[derez]

Thanks
The touch works already (slowly and jumpy on the emulator...)
The canvas is a treasure of methods !

 

[derez]

Something is missing , see the error photo.

shouldn't the dest rect be defined with reference to the target (in this case - the activity), other wise how to draw on another bitmap ?
edit: found the answer to the drawing on bitmap - by the canvas initialize2, but the error is still unclear.
edit : found that one too - the canvas wasn't initialized. now i'm happy.

 

[derez]

how can I copy part of a bitmap to another bitmap ? Using canvas - it draws only on a view.

The Jpeg library by Agraham enabled to copy part of a bitmap directly from a file, it will be good to have it here also.

 

[Erel]

You can get the bitmap that the canvas draws on with canvas.Bitmap.
This means that you use the view only as a bitmap container.

 

[derez]

Thank you. I wanted to use an imageview but couldn't get its image...
Now I hope I'll manage.

 

[derez]

File doesn't include anything on writing text to a file, after opening it, only reading, and only the whole file. How do I read a line, and write a line ?

 

[Erel]

You should use TextReader and TextWriter objects.

 

[derez]

Erel

You can get the bitmap that the canvas draws on with canvas.Bitmap.
This means that you use the view only as a bitmap container.

initializing a canvas on a view (not activity) raises an error - "width and height must be >0". I tried both imageview and a button, defined by the designer or added by code, and the size is 580x580.
Can you check please ?

 

[Erel]

This is fixed for the next update.

 

[derez]

Thank you.
now this - how do I initialize a stream ? I declared the object but there is no method for initializing it.

Sub Globals
   'These global variables will be redeclared each time the activity is created.
   'These variables can only be accessed from this module.
Dim tb1 As EditText
Dim out As EditText
Dim doit As Button
Dim tr As TextReader
Dim input As InputStream 
End Sub

Sub Activity_Create(FirstTime As Boolean)
Activity.LoadLayout("flay")
'input.initialize         ?????????????????/
tb1.Text = input.IsInitialized  ' shows false of course
tr.Initialize(input)
File.OpenInput(File.DirDefaultExternal,"central.txt")
End Sub

 

[Erel]

File.OpenInput returns an InputStream:

    Dim TextReader1 As TextReader
    TextReader1.Initialize(File.OpenInput(File.DirInternal, "central.txt"))

The following code is also fine:

    Dim TextReader1 As TextReader
    Dim InputStream1 As InputStream
    InputStream1 = File.OpenInput(File.DirInternal, "central.txt")
    TextReader1.Initialize(InputStream1)

Note that you can also declare the variables locally (if not needed globally).

 

[derez]

Thanks, it works. What is the equivalent for EOF (to check if the last read is valid ) ?

 

[Erel]

See the description for ReadLine:

 

[derez]

, there is a typo : line = Reader.rReadLine

 

[derez]

Erel

See my comment here http://www.b4x.com/forum/beta/6535-bitmap-finger-move.html#post38280, I still get an error on the same initialization line, with the new b4a version.

 

[Erel]

Can you post your code?

 

[derez]

Dim bmp As Bitmap
Dim img As ImageView
Dim cnvs As Canvas
Dim board As Canvas
Dim srect As Rect
Dim drect As Rect
Dim trect As Rect
Dim angle,cx,cy,px,py,x0,y0,a,b As Int
Dim z As Float
Dim zoomval As EditText

End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("layout1") 
   a = 2
   b = 6
   
   cnvs.Initialize(activity)
   img.Initialize(img)
   board.Initialize(img)

 

[Erel]

Sorry but I need the layout file. There is a handy tool which you can use: File - Export As Zip.