B4J Question [ non-ui ] How can i draw custom Canvas img ?

emexes

Expert
Licensed User
Did you try it?

My recollection is that you just include the graphics library (jFX, or maybe now it's jXUI) and then you can Dim a Canvas and have access to the associated drawing methods.

Then use .CreateBitmap to get the final pixels as a Bitmap which you can .WriteToStream as JPEG or PNG ready for emailing.

Admittedly, that does sound too easy to be true, so perhaps I am missing something ;-)
 
Upvote 0

DonManfred

Expert
Licensed User
Longtime User
so perhaps I am missing something
Maybe that he is writing a NONUI app. You can not include UI Elements in a NONUI app. At least that´s what i have in mind....
 
Upvote 0

Cableguy

Expert
Licensed User
Longtime User
Canvas is not a UI element so it can be used in non-ui apps, but the result cannot be attributed to a canvas capable UI element, like a button or imageview, it has to be saved thought using stream if I'm not mistaken
 
Upvote 0

klaus

Expert
Licensed User
Longtime User
You are right, it works.
Below my test code and project.

B4X:
Sub AppStart (Form1 As Form, Args() As String)
'    MainForm = Form1
    'MainForm.RootPane.LoadLayout("Layout1") 'Load the layout file.
'    MainForm.Show

    File.WriteString("D:\", "1.png", "")
    Private imv As Image
    imv.Initialize("D:\", "1.png")
    Private cvs As Canvas
    cvs.Initialize("")
    cvs.PrefWidth = 100
    cvs.PrefHeight = 100
    cvs.DrawLine(10, 10, 100, 100, fx.Colors.Red, 2)
    imv = cvs.Snapshot
    Private Out As OutputStream = File.OpenOutput("D:\", "1.png", False)
    imv.WriteToStream(Out)
    Out.Close
End Sub
 

Attachments

  • NoneUICanvasImage.zip
    1 KB · Views: 184
Last edited:
Upvote 0

Waldemar Lima

Well-Known Member
Licensed User
You are right, it works.
Below my test code and project.

B4X:
Sub AppStart (Form1 As Form, Args() As String)
'    MainForm = Form1
    'MainForm.RootPane.LoadLayout("Layout1") 'Load the layout file.
'    MainForm.Show

    File.WriteString("D:\", "1.png", "")
    Private imv As Image
    imv.Initialize("D:\", "1.png")
    Private cvs As Canvas
    cvs.Initialize("")
    cvs.PrefWidth = 100
    cvs.PrefHeight = 100
    cvs.DrawLine(10, 10, 100, 100, fx.Colors.Red, 2)
    imv = cvs.Snapshot
    Private Out As OutputStream = File.OpenOutput("D:\", "1.png", False)
    imv.WriteToStream(Out)
    Out.Close
End Sub


this works on "Console Project" application ?
 
Upvote 0

Cableguy

Expert
Licensed User
Longtime User
Non-ui and console app behave the same, IDE wise... The major difference is that you can output to screen in text format and prompt the user for text input.
 
Upvote 0

Cableguy

Expert
Licensed User
Longtime User
In a VPS, yes, it will.
It's a jar file, so it works in ANY system that is capable of running a jar file!
 
Upvote 0

MarkusR

Well-Known Member
Licensed User
Longtime User
hmm, in a linux vps enviroment u can have trouble to make a ui app auto run (start at/after boot)
 
Upvote 0
Top