Frequently Asked Questions

D-Type PowerDoc Engine

Q1: Does D-Type PowerDoc Engine have the ability to render wrapped text within a text area but clip vertically instead of deeming the text non-visible because it doesn’t completely fall within the text area rectangle?

A: In the D-Type PowerDoc Engine API, a text area is defined as an array of characters or glyphs drawn within the bounds of a rectangular area and formatted according to user-supplied parameters. This is true for both Simple Text Areas and Rich Text Areas, and applies equally to text written in rows (most world’s scripts) and columns (sometimes CJK scripts).

Thus, if we take the above definition into account and interpret the question precisely as asked, the answer is no; PowerDoc text areas are not designed to clip their own content based on the outcome of text layout operations. In fact, with D-Type PowerDoc Engine, clipping is not an operation associated with any particular PowerDoc object (a text area in this instance) but rather with the overall output, encompassing all objects on a PowerDoc page. The closest operation applicable to individual PowerDoc objects is alpha-masking, which is a more general and more powerful concept than clipping (as it involves using an alpha channel of another group of objects to determine the visibility or transparency of pixels, allowing for clipping and other complex visual effects). However, it is important to note that alpha-masking is typically slower than simple rectangular clipping (also known as window clipping), so it will not be suggested as the right answer to the above question or discussed further here.

On the other hand, if the question is interpreted a bit more freely and with the assumption that only simple window clipping is needed, then the answer is yes. D-Type PowerDoc Engine supports text areas where the width and/or height is infinite, as documented in the PowerDoc object design specifications. This allows applications to create a text area with a finite width (to support wrapped horizontal text) but infinite height (to ensure that all text fits vertically and is never deemed non-visible). Subsequently, applications can clip the overall output to any desired rectangle within the rendering surface, likely achieving the intended result.

Note that a similar approach can also be applied to text laid out in columns. In this case, applications would create a text area with a finite height (to support wrapped vertical text) but infinite width (to ensure that all text fits horizontally and is never deemed non-visible), and subsequently clip the overall output to any desired rectangle within the rendering surface.