CurrentX not working with Text

[dragonjim]

Hi,

I'm trying to find the length of text printed into the main window so I thought I would use CurrentX as a variable as follows:

CurrentX = 0
Text 1,1,"Hello"
New_Pos = CurrentX

However, New_Pos returns 0.

Is this a known bug? And does anyone know of a way of judging the length of text in a certain font, size, etc. My aim is to print the text centrally at the top of the window...

[649psoft2]

No there is no bug. This is a difficult task with the
general primitive text draw command to be sized
and positioned on device context dimentions that
are different for each screen display and scalemode.

here is the code for your objective:

CurrentX = 0

Text 1, 1, "Hello"
Local a$ = "Hello"

Local New_Pos% = 20

'no bug
Text New_Pos%, 20, a$

'see support.microsoft.com/kb/74298

Local TextLen%

'use VarPtr pointer to a$

'this is a complex point to draw a primitive on a display
'device context dependent on the screen aspect ratio
'and scalemode

TextLen% = Int(GetTextExtent(Me.hDC, V:a$, 5))
TextLen% = TextLen% / (Me.TwipsPerPixelX * 288) / GetDevCaps(ASPECTXY)

'show the centered text drawn in red arbitrarily spilt to center
Color RGB(255, 0, 0)
Text (Me.Width / Me.TwipsPerPixelX / 2) + (Me.Width / (TextLen% * 144) / 2), 30, a$

MsgBox "click mouse to exit"

Do : Sleep : Until MouseK > 0

DoEvents 'remaining messages

CloseW 1

[649psoft2]

except the last line half of the length of the "hello" text is added past the center
of the window

Text (Me.Width / Me.TwipsPerPixelX / 2) - (Me.Width / (TextLen% * 144) / 2), 30, a$

splits the "hello" in the center.

[dragonjim]

Hi 649psoft2,

Thanks for that - my understanding is that, according to the helpfile, "the CurrentX and CurrentY settings are changed [for] [Gray]Text [to] The right bottom corner of the text" which doesn't seem to happen.

Thank you for your sample text - I've tried it and it seems to work for 'hello' but if I replace 'hello' with a longer word - say 'goodbye' - it seems to return the centre position for 'hello'. Am I missing something? I have tried changing the last figure ('5') in the GetTextExtent function to the number of letters in the word I need to centre (I'm not totally sure of the purpose of this last variable), but this made no difference.

I wonder if one of the other constants needs to be changed in order to cater for a longer word? That said, however, when I tried a longer word, the value returned by GetTextExtent appeared to be the same, so maybe there is something there that needs changing.

Thank you once again for your reply and I hope you may be able to help me with the problems I am experiencing getting your example to work.

[dragonjim]

Eureka!!

Good old GFA Basic comes up trumps again. Hidden away deep in the help file is the little function TextWidth(t$) which returns length of the string t$ in pixels. Combine this with the _X constant (or Me.Width/TwipsPerPixelX, though this seems to give a slightly different result to _X) and centring is possible, as well as so much more!

Just out of interest: TextWidth (as with GetTextExtent) does NOT cater for Italic overhang (usually an extra pixel at the end of the string) but (like GetTextExtent) does adjust for emboldened characters.

[649psoft2]

'I was a bit hasty my last example
'beleive it or not that was about the
'top and only reference and microsoft.com
'It is 16 bit and has been replaced!

'by GetTextExtentPoint32 modifed at least
'half a dozen times with alias names

'hope this helps
'I recommend Win32 SDK Online Help
'from MSDN

'Example 1

'CurrentX

'appears to be assigned just like any other variable

OpenW 1

'documentation says right bottom should be top right
CurrentX = 0
CurrentY = 0
Text CurrentX, CurrentY, "Hallo..ooh"

CurrentX = 60
CurrentY = 100
Text CurrentX, CurrentY, "Hallo..ooh"

With Win_1
'center of circle CurrentX is text left CurrentX
CurrentX = 60
CurrentY = 100
Circle CurrentX, CurrentY, 60
EndWith

MsgBox "Press a key to exit"
CloseW 1

'Example 2

'GetTextExtentPoint32

'The GetTextExtentPoint32
'function computes the width and height of the
'specified string of text. This function supersedes
'the GetTextExtentPoint function.

'strangely there is no more GetTextExtentPoint32
'in my gdi32.Dll

'but this appears to work in gfa basic

'GetTextExtent '16 bit
'GetTextExtentPoint 'win 95 win 32
'GetTextExtentPoint32 'corrected again 32 bit

'superceded
'Alais GetTextExtentPoint32A
'Alais GetTextExtentPoint32W
'Alais GetTextExtentPoint32I

Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
EndType

Type SIZE
cx As Long
cy As Long
EndType

Local TxtSz As SIZE
Local ret As Long
Local a$, b%

OpenW 1

a$ = "Hello"

' GetTextExtentPoint32(long handle to device context,
' long pointer to string, int length of string,
' pointer to size structure)

Text 10, 10, a$
Text 10, 30, "characters=" + Str(Len(a$))
ret = GetTextExtentPoint32(Win_1.hDC, V:a$, Len(a$), V:TxtSz)
Text 10, 50, "height=" + Str(TxtSz.cy)
Text 10, 70, "length=" + Str(TxtSz.cx)

a$ = "HelloHello"
Text 10, 110, a$
Text 10, 130, "characters=" + Str(Len(a$))
ret = GetTextExtentPoint32(Win_1.hDC, V:a$, Len(a$), V:TxtSz)
Text 10, 150, "height=" + Str(TxtSz.cy)
Text 10, 170, "length=" + Str(TxtSz.cx)

With Win_1
.AutoRedraw = True 'for paint redraw on graphics
.Font.Bold = True 'font properties
.Font.Italic = True
.Font.Name = "Arial"
.Font.Strikethrough = False
.Font.Underline = False
.Font.Size = 12
.ForeColor = RGB(0, 255, 0)
EndWith

Local Win1Rect As RECT
~GetWindowRect(Win_1.hWnd, Win1Rect)
Local WidthPixels = Win1Rect.Right - Win1Rect.Left

Text 10, 230, "characters=" + Str(Len(a$))
ret = GetTextExtentPoint32(Win_1.hDC, V:a$, Len(a$), V:TxtSz)
Text 10, 250, "height=" + Str(TxtSz.cy)
Text 10, 270, "length=" + Str(TxtSz.cx)
Text 10, 290, "window width=" + Str(WidthPixels)

Local MidPoint = (WidthPixels / 2) - (TxtSz.cx / 2)

Text MidPoint, 210, a$

Color RGB(255, 0, 0)
Text 10, 340, "Press a key to exit"
KeyGet b%

CloseW 1

[dragonjim]

Thanks for that - it certainly clears up why I could only find references to GetTextExtent for Adobe Flash!