Text Objects - Determining Text Size
Alex Eastwood
I am trying to find a way of extracting the font size from an existing Text object. There is no direct way to do this via the ObjectInfo() function, so as a workaround I have tried something like this:
Dim oObj,oMBR as Object
Dim Top,Bottom,TextHeight as Float
oObj = Selection.Obj
Alter Object oObj Geography OBJ_GEO_TEXTANGLE,0 'make it horizontal
Update Selection Set Obj = oObj
oMBR - MBR(oObj) [MinimumBoundingRectangle]
Top = ObjectGeography(oMBR,OBJ_GEO_MAXX)
Bottom = ObjectGeography(oMBR,OBJ_GEO_MINX)
TextHeight = Top - Bottom
The problem with this is that the text objects are often not horizontal (which they need to be for 'Top' and 'Bottom' to be correct), hence Alter Object...TextAngle, but this Alter Object statement also modifies the size of the text object for some reason. So when you then define the MBR after you've rotated the text object the size won't be correct.
When you are making text objects there is of course the Font clause where one can specify size, style etc. so the information I need must be stored somewhere, but I can't find a way to extract from an existing object.
Hope all the above is clear, many thanks in advance for any help/suggestions!
Alex
GIS Software Developer, Buchanan Computing
London, UK
Thomas Bacon
Alex,
I stumbled upon this problem recently and deduced that this was due to the fact that any font size would only be correct at 1 specific map zoom as the font scales with the zoom. I guess using the object bounds as you’ve done would be the only way to get a size for the text. If there is another way I’d be interested to hear it too!
Cheers,
Tom Bacon
GIS Engineer, Mouchel
T 01444 472380 │ E thomas...@mouchel.com │ W www.mouchel.com
Our values: innovation │ excellence │ integrity │ responsibility
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Thomas Bacon
“The problem with this is that the text objects are often not horizontal (which they need to be for 'Top' and 'Bottom' to be correct), hence Alter Object...TextAngle, but this Alter Object statement also modifies the size of the text object for some reason. So when you then define the MBR after you've rotated the text object the size won't be correct.”
I guess the text size must be defined by its MBR so rotating the text would affect the way it fits inside the bounding rectangle and hence the size of the text. I’m not sure how you’d calculate the height and width in this case!
Tom Bacon
GIS Engineer, Mouchel
T 01444 472380 │ E thomas...@mouchel.com │ W www.mouchel.com
Our values: innovation │ excellence │ integrity │ responsibility
From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com]
On Behalf Of Alex Eastwood
Sent: 17 April 2015 14:48
To: mapi...@googlegroups.com
Subject: [MI-L] Text Objects - Determining Text Size
Hi,
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Tony Pilkington
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Alex Eastwood
I see what you mean regarding the different font size at different map scales, that would explain why there is no function for extracting the font size from text objects. For the data I'm using the size is actually fixed - not that that brings us any further in this case.
My colleague has been in touch with Pitney Bowes regarding this, but unfortunately they haven't provided us with a magical solution (yet...?)!
I also found that if you select a Text Object and rotate it manually (ie with the mouse by clicking on the rotation node) as opposed to rotating it via the MapBasic command the size is preserved...
We'll be trying to come up with a workaround for this so I'll keep you posted!
Cheers,
Alex
Alex Eastwood
Text height for this data is fixed, not sure how I would use the current zoom level to extract the text height...? Bearing in mind I have 400k objects I'm trying to do this with so this all needs to be automated and wouldn't actually be displayed in a map window or otherwise!FONT_POINTSIZE:
Integer indicating the Font size, in points.
Note: If the Text object is in a mappable table (as opposed to a Layout window), the point size is returned as zero, and the text height is dictated by the Map window's current zoom.
Cheers,
Alex
Greg
Many years ago, Jacques Paris investigated text objects and produced an informative document, which included some MapBasic functions to find text size etc. He also covered the use of the MBR() to find the size and how it changes if the text object has been rotated. I may have a copy, if it can't be found on-line.
Greg
Bill Thoen
Bo Victor Thomsen
http://georezo.net/jparis/
The specific document about text size in MapInfo is here:
http://georezo.net/jparis/d_a/textobjects/MI_Text_Objects.zip
AFAIK It's still relevant :-/ The representation of text in MapInfo in
still slightly zany
Regards
Bo Victor Thomsen
AestasGIS
Denmark
Greg
Greg
Bill Thoen
> That's the one, thanks Bill. Wow, written in 2003....
>
> Greg
>
Alex Eastwood
I'm going to give the TextSize() function a go, but I'm not sure if this will work for this particular purpose.
Otherwise I might write a function based on that document by Jacques Paris where you can calculate the size of a non-horizontal text bounding rectangle (page 7).
I'll let youse know how I get on!
Thanks again,
Alex
Eric Blasenheim
Alter Object oObj Geography OBJ_GEO_TEXTANGLE,0 'make it horizontal ' A text object has an internal size that represents the unrotated height of the text in table units (the units of the coordinate system). When you change the angle, the height is not changed, so you have essentially changed the bounding box as we rotate the text keeping the size.
Update Selection Set Obj = oObj ' note that this operation could change things if the coordinate system of oObj and the table are not the same because a coordinate system transformation would occur.
Top = ObjectGeography(oMBR,OBJ_GEO_MAXX)
Bottom = ObjectGeography(oMBR,OBJ_GEO_MINX)
Alex Eastwood
thanks for your response. Regarding what I said about the text size being fixed, what I mean is that once the text object has been drawn on a map, its size in distance units is fixed, i.e. when you zoom out the text becomes too small to read. This as opposed to labels for example, where the size stays constant regardless of the zoom level.
In terms of what I am trying to achieve:
We have map data where road names, building names etc are stored as text objects. These data are being uploaded to the web via a series of tiles, which are rendered on the fly as the user pans the map. The problem we are having is that if a text object spreads across 2 adjacent tiles the text is truncated, so we have written a program that converts each letter of a text object into a region, combines the regions into a word and then adds these to the map. This way the regions don't get truncated between neighbouring map tiles.
We have had 1 dataset where the text size in distance units was indicated as part of the data, and we created our text regions based on this height. For all other data, this is not the case, hence why we are using MBRs around the text object to try and get an idea of how large the text is, so that our region text can be similar in size. But since most of the text objects are not horizontal, the height derived from the MBR is not correct until we have rotated it to horizontal, which is when we found that doing this via the method described above changes the height of the object.
We have been trying various methods based on Jacques Paris's TextBoxSize function, and have made some progress. I'll post an update on this tomorrow since I'm leaving the office now.
Thanks again,
Alex
Eric Blasenheim
On Friday, April 17, 2015 at 10:46:26 AM UTC-4, Alex Eastwood wrote:
Alex Eastwood
we are using Open Layers 3 for this, it does read the text objects but clearly doesn't handle them very well. I think we're stuck with it now so will have to find ways to deal with it! But I'm not in a position to judge, I've just been tasked with processing data for uploading to the web.
Anyway we've almost got something usable, I'll keep everyone posted.
Cheers,
Alex
Alex Eastwood
have been busy with other stuff over the last few weeks, but thought I should post an update for everyone who offered to help:
I ended up using a very slightly TextBoxSize() function, which can be found via this link http://georezo.net/jparis/d_a/textobjects/text_objects.htm (Thanks Jacques!). This works reasonably well, except for text rotated at 45°. This is probably stated somewhere in Jacques' text so might not be a great revelation to anyone, however we did try getting around it by nominally adding/subtracting a few 0.1°s to/from the text angle if this was 45°. Jacques does something similar (subtracts 0.00001 from the text angle) when the text angle is a multiple of 45, and both his and our method work well enough, except where the angle is actually 45 (not a multiple). If I remember correctly anything with an angle between 44.1° and 45.8° would produce strange/unusable results, so we decided to skip everything with these angles, and resize the text to a nominal value. It is interesting that a couple of tenths of a degree can make a big difference, in some cases text rotated at 44° would come out fine, whereas text of a similar length & height rotated at 44.2° would come out completely wrong. But I for one am unable to explain why this happens.
So, unfortunately there is no happy ending to this story, no 'happily ever after', no Prince Charming who came to the rescue. We had a crack at it and failed, but we live to code another day.
Thanks again to everyone for your suggestions and interest, if I have a 'hallelujah moment' I'll let youse all know.
Cheers,
Alex
Thomas Bacon
Thanks for the update Alex, and also the link. Good to have this reference as I’m sure I’ll end up trying to do similar at some point!
Cheers,
Tom Bacon
GIS Engineer, Mouchel
T 01444 472380 │ E thomas...@mouchel.com │ W www.mouchel.com
Our values: innovation │ excellence │ integrity │ responsibility
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Robert Crossley
Thomas,
I was looking at this problem a while ago as I wanted to store text objects in SQL Server by storing their properties separately to the object, and then recreating the text object from those properties. Unfortunately, there was one property that couldn’t be accessed from MapBasic, something like the unrotated height.
So I pass my test program to you to see if you can make any more progress than I. The code has lost its formatting I am afraid. Good luck.
Rob.
Sub Main
Create Table "TestTextObj" (ID Integer) File ApplicationDirectory$() + "TestTextObj.tab"
Create Map For TestTextObj CoordSys Earth Projection 1,104
fFont = MakeFont("Arial", 1, 12, BLACK, -1)
Create Text Into Variable oTextObj
"Looooooooooong Test String 0"
(153,-24) (153.1, -24.1)
Font fFont
Angle 0
Insert Into TestTextObj (ID, Obj) Values (-1, oTextObj)
Insert Into TestTextObj (ID, Obj) Values (0, MBR(oTextObj))
Create Text Into Variable oTextObj
"Looooooooooong Test String 30"
(153,-25) (153.1, -25.1)
Font fFont
Alter Object oTextObj Geography OBJ_GEO_TEXTANGLE, 30
Insert Into TestTextObj (ID, Obj) Values (-1, oTextObj)
Insert Into TestTextObj (ID, Obj) Values (0, MBR(oTextObj))
Create Text Into Variable oTextObj
"Looooooooooong Test String 225"
(154,-25) (154.1, -25.1)
Font fFont
Alter Object oTextObj Geography OBJ_GEO_TEXTANGLE, 225
Insert Into TestTextObj (ID, Obj) Values (-1, oTextObj)
Insert Into TestTextObj (ID, Obj) Values (0, MBR(oTextObj))
Create Text Into Variable oTextObj
"Looooooooooong Test String 90"
(154.5,-25) (154.6, -25.1)
Font fFont
Alter Object oTextObj Geography OBJ_GEO_TEXTANGLE, 90
Insert Into TestTextObj (ID, Obj) Values (-1, oTextObj)
Insert Into TestTextObj (ID, Obj) Values (0, MBR(oTextObj))
Create Text Into Variable oTextObj
"Looooooooooong Test String 125"
(155,-25) (155.1, -25.1)
Font fFont
Alter Object oTextObj Geography OBJ_GEO_TEXTANGLE, 125
Insert Into TestTextObj (ID, Obj) Values (-1, oTextObj)
Insert Into TestTextObj (ID, Obj) Values (0, MBR(oTextObj))
Commit Table TestTextObj
Close Table TestTextObj
Open Table ApplicationDirectory$() + "TestTextObj.tab"
Map From TestTextObj
Set Map Window FrontWindow() Zoom Entire
Create Menu "Test Object Functions" As
"Do Text Operations" Calling TransformText
Alter Menu Bar Add "Test Object Functions"
End Sub
Sub TransformText
'-----------------------
'Subroutine: Main
'Called By: None
'Description: This subroutine calls other subs to sets up the menus and initial variables.
'-----------------------
'Set up general error handler
ONERROR GOTO ErrorHandler
Dim oOrigTextObject, oMBROrigTextObject, oMBRotatedTextObj, oNewTextObj As Object
Dim oObjProp As tObjProperties
'Dim oMBROrigText As tObjMBX
Dim RotationAngle As Float
Dim arraysize As Integer
Select * From TestTextObj Where ID > 0 Into SelText
Delete From SelText
Select * From TestTextObj Where ID <= 0 Into SelText
If TableIsOpen("TmpObjects") Then
Drop Table TmpObjects
End If
Create Table "TmpObjects" (TextRotation Float) File ApplicationDirectory$() + "TmpObjects.tab"
Create Map For TmpObjects CoordSys Earth Projection 1,104
Select * From TestTextObj Where Obj Into SelTemp
Select * From SelTemp Where Int(ObjectInfo(Obj, OBJ_INFO_TYPE)) = OBJ_TYPE_TEXT Into SelTempText
If SelectionInfo(SEL_INFO_NROWS) > 0 Then
Insert Into TmpObjects (TextRotation, Obj) Select ObjectGeography(Obj, OBJ_GEO_TEXTANGLE), Obj From SelTempText
End If
Select * From SelTemp Where Int(ObjectInfo(Obj, OBJ_INFO_TYPE)) <> OBJ_TYPE_TEXT Into SelTempNotText
If SelectionInfo(SEL_INFO_NROWS) > 0 Then
Insert Into TmpObjects (TextRotation, Obj) Select 0, Obj From SelTempNotText
End If
Select * From TmpObjects Into SelTemp
Update SelTemp Set Obj = fUnRotateText(Obj)
If SelectionInfo(SEL_INFO_NROWS) > 0 Then
Fetch First From SelTemp
Do Until EOT(SelTemp)
If fGetObjProperties(SelTemp.Obj, oObjProp) = FALSE Then
Note "Failed to extract properties from text object."
Else
oOrigTextObject = SelTemp.Obj
oObjProp.iTextAngle = SelTemp.TextRotation
'RotationAngle = ObjectGeography(oOrigTextObject, OBJ_GEO_TEXTANGLE)
'oMBROrigTextObject = MBR(oOrigTextObject)
'Insert Into TestTextObj (ID, Obj) Values (1, oMBROrigTextObject)
oNewTextObj = fCreateObjFromProperties(oObjProp.iObjectType,
oObjProp.cTextString,
oObjProp.cFontName,
oObjProp.IfontStyle,
oObjProp.IfontSize,
RED,
oObjProp.IfontbackColor,
oObjProp.iTextSpacing,
oObjProp.iTextJustIfy,
oObjProp.iTextLineType,
oObjProp.cTextLinePen,
oObjProp.fTextLineX,
oObjProp.fTextLineY,
oObjProp.iTextAngle,
oObjProp.oObj)
Insert Into TestTextObj (ID, Obj) Values (3, oNewTextObj)
End If
Fetch Next From SelTemp
Loop
End If
Exit Sub
ErrorHandler:
Note Error$()
End Sub
Function fUnRotateText(ByVal oObj As Object) As Object
'-----------------------
'Subroutine: Main
'Called By: None
'Description: This subroutine calls other subs to sets up the menus and initial variables.
'-----------------------
'Set up general error handler
ONERROR GOTO ErrorHandler
Dim oUnRotObj As Object
Dim iTextAngle, iObjectType As Integer
iObjectType = ObjectInfo(oObj, OBJ_INFO_TYPE)
Do Case iObjectType
Case OBJ_TYPE_TEXT
iTextAngle = ObjectGeography(oObj,OBJ_GEO_TEXTANGLE)
If iTextAngle <> 0 Then
Alter Object oObj Geography OBJ_GEO_TEXTANGLE, 0
End If
Case Else
fUnRotateText = oObj
End Case
Exit Function
ErrorHandler:
CALL ErrorMessage("fUnRotateText")
END Function 'fUnRotateText
Function fCreateObjFromProperties(ByVal iObjectType As SmallInt,
ByVal cTextString As String,
ByVal cFontName As String,
ByVal iFontStyle As Integer,
ByVal iFontSize As Integer,
ByVal iFontForeColor As Integer,
ByVal iFontbackColor As Integer,
ByVal fTextSpacing As Float,
ByVal iTextJustify As SmallInt,
ByVal iTextLineType As SmallInt,
ByVal cTextLinePen As String,
ByVal fTextLineX As Float,
ByVal fTextLineY As Float,
ByVal iTextAngle As Integer,
ByVal oObj As Object) As Object
'-----------------------
'Subroutine: Main
'Called By: None
'Description: This subroutine calls other subs to sets up the menus and initial variables.
'-----------------------
'Set up general error handler
ONERROR GOTO ErrorHandler
Dim oText As Object
Dim fFont As Font
Dim UnRotText As Object
Dim oMBRUnRotText As Object
Dim Xi As Float
Dim Hi As Float
Dim Xr As Float
Dim Hr As Float
Dim K As Float
Dim a As Float
Dim b As Float
Dim Discriminant As Float
' ------------
' | / /|
' | / / |
' | / / |
' | / /Xi |
' | / / |
' | /Hi/ |
' ------------
' a b
' Xr
If iFontSize = 0 Then
iFontSize = 100
End If
If iObjectType <> OBJ_TYPE_TEXT Then
fCreateObjFromProperties = oObj
Exit Function
Else
fCreateObjFromProperties = oObj
fFont = MakeFont(cFontName, iFontStyle, iFontSize, iFontForeColor, iFontbackColor)
If iTextAngle = 0 Then
Print "Found a ext object with a text andgle of 0"
Create Text Into Variable oText
cTextString
(ObjectGeography(oObj, OBJ_GEO_MINX), ObjectGeography(oObj, OBJ_GEO_MINY)) (ObjectGeography(oObj, OBJ_GEO_MAXX), ObjectGeography(oObj, OBJ_GEO_MAXY))
Font fFont
Spacing fTextSpacing
Else
Print "Found a ext object with a text andgle of " + iTextAngle
Create Text Into Variable UnRotText
cTextString
(ObjectGeography(oObj, OBJ_GEO_MINX), ObjectGeography(oObj, OBJ_GEO_MINY)) (ObjectGeography(oObj, OBJ_GEO_MAXX), ObjectGeography(oObj, OBJ_GEO_MAXY))
Font fFont
Spacing fTextSpacing
'Get proportion of hieght to base on text object.
oMBRUnRotText = MBR(UnRotText)
K = (ObjectGeography(oMBRUnRotText, OBJ_GEO_MAXX)- ObjectGeography(oMBRUnRotText, OBJ_GEO_MINX))/ (ObjectGeography(oMBRUnRotText, OBJ_GEO_MAXY) - ObjectGeography(oMBRUnRotText, OBJ_GEO_MINY))
Print "K Len/ Height of Unrotated Text = " + K
Xr = ObjectGeography(oObj, OBJ_GEO_MAXX) - ObjectGeography(oObj, OBJ_GEO_MINX)
Print "Xr= " + Xr
Hi = Xr / (Sin(iTextAngle*DEG_2_RAD) + (K * Cos(iTextAngle*DEG_2_RAD)))
' Discriminant = (Xr ^ 2) - (4 * Sin(-1*iTextAngle*DEG_2_RAD) * K * Cos(iTextAngle*DEG_2_RAD))
' Print "Discriminant= " + Discriminant
' Hi = ((-1 * Xr) + Sqr(Discriminant)) / (-2 * Sin(iTextAngle*DEG_2_RAD))
' Hi = ObjectGeography(oMBRUnRotText, OBJ_GEO_MAXY) - ObjectGeography(oMBRUnRotText, OBJ_GEO_MINY)
Print "Hi= " + Hi
Create Text Into Variable oText
cTextString
(ObjectGeography(oObj, OBJ_GEO_MINX), ObjectGeography(oObj, OBJ_GEO_MINY)) (ObjectGeography(oObj, OBJ_GEO_MAXX), ObjectGeography(oObj, OBJ_GEO_MAXY))
' (ObjectGeography(oObj, OBJ_GEO_MINX), ObjectGeography(oObj, OBJ_GEO_MINY)) (ObjectGeography(oObj, OBJ_GEO_MAXX), ObjectGeography(oObj, OBJ_GEO_MINY)+Hi)
Font fFont
Spacing fTextSpacing
Angle iTextAngle
End If
If iTextLineType In(0,1,2) Then
Alter Object oText Info OBJ_INFO_TEXTARROW, iTextLineType
End If
If fTextLineX > 0 Then
Alter Object oText Geography OBJ_GEO_TEXTLINEX, fTextLineX
End If
If fTextLineY > 0 Then
Alter Object oText Geography OBJ_GEO_TEXTLINEY, fTextLineY
End If
fCreateObjFromProperties = oText
End If
Exit Function
ErrorHandler:
CALL ErrorMessage("fCreateObjFromProperties")
END Function 'fCreateObjFromProperties
From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] On Behalf Of Thomas Bacon
Sent: Wednesday, 13 May 2015 7:54 PM
To: mapi...@googlegroups.com