Bounding Box Top Left Hand Corner Attribute
| Tag | (0070,0010) |
|---|---|
| Type | Optional (3) |
| Keyword | BoundingBoxTopLeftHandCorner |
| Value Multiplicity | 2 |
| Value Representation | Single (FL) |
Recommended location of the Top Left Hand Corner (TLHC) of the bounding box in which Unformatted Text Value (0070,0006) is to be displayed, as fractions of the specified presentation view width and height. Each value shall be within the range 0.0 to 1.0.
See Section C.10.5.1.1.
Section C.10.5.1.1
C.10.5.1.1 Unformatted Text Value
The text shall be displayed if any part of the bounding box or anchor point is within the Specified Display Area.
The text need not be confined to within the bounding box, but shall be rendered in a direction from the Top Left Hand Corner (TLHC) of the bounding box to the Bottom Right Hand Corner (BRHC) of the bounding box, even if these coordinates have been specified in an image relative space and then transformed (rotated, flipped or scaled).
Note
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An implementation may render text outside the confines of the bounding box if necessary to display all the specified text.
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Alternatively, an implementation may choose to render the text in a scrolling box, or a link to another fixed or popup window as appropriate.
Whether the contents of the bounding box completely opacify the underlying image or whether the box is "transparent" is undefined.
Note
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For example, an implementation may choose an "exclusive or" style opacification to be sure that the text is discernible over light and dark portions of the image.
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Commonly, the region of the bounding box around the text will be rendered "transparently", i.e., the image will be visible, though some implementations may choose to opacify the bounding box behind the text to improve its readability.
An alternative to specifying a bounding box, is to specify an Anchor Point (0070,0014), i.e., some point in an image or Specified Displayed Area that is related to the text. The semantics of this relationship, and the manner of positioning or linking the text to this point, are unspecified.
Note
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For example, a description of a feature may be linked to a point in the image, and when that image is displayed, if it is magnified and panned, the rendered text (and any arrow or line drawn in response to Anchor Point Visibility (0070,0015)) might be repositioned as appropriate so as not to be cropped out of the Specified Displayed Area.
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As another example, the text could be rendered in a pop-up window when a hypertext link flagged on the displayed image at the location of Anchor Point (0070,0014) is selected.
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The bounding box and anchor point need not be defined with the same axis units, i.e., one can be image pixel relative, and the other displayed area relative.
The size, font and rotation of the individual rendered text characters are unspecified.