Re: Centreing and Rotating Text

Hi Paul,

Thanks for the bug report! I've updated the code for the next release.

- Don

On Tuesday, October 23, 2001, at 07:09 PM, Paul Chisholm wrote:

> HI Don,
>
> thanks for the info. I have looked at it a bit further and I think
> there may
> be a small defect in the OMText class. You say the rotation point is the
> defined lat/lon point. Below is a snippet from the 'render' method:
>
> if (g instanceof Graphics2D && rotationAngle !=
> DEFAULT_ROTATIONANGLE) {
> computeBounds();
> Rectangle rect = polyBounds.getBounds();
>
> rx = rect.getX();
> ry = rect.getY();
> rw = rect.getWidth();
> rh = rect.getHeight();
> woffset = 0.0;
>
> ....some code to set woffset....
>
> //rotate about our text anchor point
> ((Graphics2D)g).rotate(rotationAngle, rx+woffset, ry);
> }
>
> Note in the call to 'rotate' the y point is 'ry' where 'ry' is set to
> the y
> co-ordinate of the bounding box. Looking at the javadoc page for class
> Recangle it states
>
> "A Rectangle specifies an area in a coordinate space that is enclosed
> by the
> Rectangle object's top-left point (x, y) in the coordinate space, its
> width,
> and its height."
>
> So OMText is based on the bottom of the bounding box while Rectangle is
> based on the top. This would explain why my testing suggested rotation
> was
> taking place about the top of the text. I subclassed OMText providing an
> alternate 'render' method that sets 'ry' to the bottom of the bounding
> box
> and got a satisfactory result.
>
> Paul
>
> ----- Original Message -----
> From: "Donald Dietrick" <dietrick@bbn.com>
> To: "Paul Chisholm" <paulch@bigpond.com>
> Cc: <openmap-users@bbn.com>
> Sent: Tuesday, October 23, 2001 9:51 PM
> Subject: Re: Centreing and Rotating Text
>
>
> Hi Paul,
>
> The rotation point is the defined lat/lon point, so if you want to
> control where your text is relative to that point, you can use a offset
> render type, where you give a pixel offset as well as the lat/lon
> point. I don't think you'd have to give a horizontal offset if you
> choose center justification, but you might have to supply a vertical
> offset to put the center of the text on the lat/lon point. You also may
> have to create the OMText object, generate it to figure out how tall it
> is (pixelwise), and then reset the vertical offset and regenerate().
> You should only have to do that once, though.
>
> Cheers,
>
> Don
>
>
>
> On Monday, October 22, 2001, at 11:05 PM, Paul Chisholm wrote:
>
>> I am struggling a bit with a problem. I want to place a piece of text
>> in a layer with the text centred on a point. That is the centre of the
>> text, not the mid-point of the baseline. I then want to rotate the text
>> about the centre point.
>>
>> I have tried some things but cant seem to come up with an acceptable
>> solution. The point I want to centre the text on is expressed as a
>> Lat/Long.
>>
>> From my testing it seems the text is rotated about the top of the text.
>>
>> Paul
>>
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Donald Dietrick, dietrick@bbn.com
BBN Technologies, Cambridge, MA
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
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