Wish B4X XUI Add MeasureTextWidth and MeasureTextHeight to B4XCanvas

[klaus]

Hi Erel,
The title says the wish.
Currently, there are three different routines in the class with different results.
Example:
MeasureTextHeight("Mg") and MeasureTextHeight("M") give different results in B4A because the real height is different, but give the same result in B4J.
I have not checked with B4i.

 

[Erel]

Which method are you using to measure the text dimensions in B4J?

 

[klaus]

I use this code in the xChart class:

Private Sub MeasureTextWidth(Text As String, Font1 As B4XFont) As Int
#If B4A
    Private bmp As Bitmap
    bmp.InitializeMutable(2dip, 2dip)
    Private cvs As Canvas
    cvs.Initialize2(bmp)
    Return cvs.MeasureStringWidth(Text, Font1.ToNativeFont, Font1.Size)
#Else If B4i
    Return Text.MeasureWidth(Font1.ToNativeFont)
#Else If B4J
    Dim jo As JavaObject
    jo.InitializeNewInstance("javafx.scene.text.Text", Array(Text))
    jo.RunMethod("setFont",Array(Font1.ToNativeFont))
    jo.RunMethod("setLineSpacing",Array(0.0))
    jo.RunMethod("setWrappingWidth",Array(0.0))
    Dim Bounds As JavaObject = jo.RunMethod("getLayoutBounds",Null)
    Return Bounds.RunMethod("getWidth",Null)
#End If
End Sub

Private Sub MeasureTextHeight(Text As String, Font1 As B4XFont) As Int
#If B4A    
    Private bmp As Bitmap
    bmp.InitializeMutable(2dip, 2dip)
    Private cvs As Canvas
    cvs.Initialize2(bmp)
    Return cvs.MeasureStringHeight(Text, Font1.ToNativeFont, Font1.Size)
#Else If B4i
    Return Text.MeasureHeight(Font1.ToNativeFont)
#Else If B4J
    Dim jo As JavaObject
    jo.InitializeNewInstance("javafx.scene.text.Text", Array(Text))
    jo.RunMethod("setFont",Array(Font1.ToNativeFont))
    jo.RunMethod("setLineSpacing",Array(0.0))
    jo.RunMethod("setWrappingWidth",Array(0.0))
    Dim Bounds As JavaObject = jo.RunMethod("getLayoutBounds",Null)
    Return Bounds.RunMethod("getHeight",Null)
#End If
End Sub

I had found the code for B4J in the forum.
Looking closer on the B4J code, I think I understand why the heights are the same.
There is probably another method to get the height.

 

[Erel]

Try it with this code: https://www.b4x.com/android/forum/threads/measure-multiline-text-height.84331/#content

 

[klaus]

Hi Erel,
The main reason of this thread is the wish to add MeasureTextWidth and MeasureTextHeight methods to the B4XCanvas object.
I mentioned the height differences as an information, the code in post #3 works for what I need in the xChart class.
The wish is to have method directly in B4XCanvas instead of three routines in the class.

Try it with this code: https://www.b4x.com/android/forum/threads/measure-multiline-text-height.84331/#content

Returns the same value as the code in post #3.

Log(MeasureMultilineTextHeight(mFont, 100, "Mg"))
Log(MeasureMultilineTextHeight(mFont, 100, "M"))
Log(MeasureTextHeight("Mg", mFont))
Log(MeasureTextHeight("M", mFont))

All four Logs give the same value