Set Projection

Purpose

The Set Projection function indicates to the DWF reading application what portion of the logical coordinate space is viewed.

Syntax

Proj A description of how the selected view is projected into the containing window.

Details

The Set Projection opcode specifies how the DWF reading application handles the case when the aspect ratio of the selected View does not equal the aspect ratio of the window into which the view is projected. Legal values for Proj include the following:

• normal- The selected view is symmetrically scaled so that it completely fits within the containing window without distortion. In the case that the window's aspect ratio is larger than the view's aspect ratio, the view is scaled such that, horizontally, it fits tightly within the containing window. However, the view is scaled vertically such that a larger region of the logical coordinate space is viewed than was requested. When the window's aspect ratio is less than the view's aspect ratio, the view fits tightly in the vertical direction, and an excess of logical space is viewed horizontally (from what was requested).
• stretch- The selected view is asymmetrically scaled so that it exactly fills the containing window in both dimensions, and thus is distorted when the aspect ratios differ (circles become ellipses).
• chop- Similar to normal, however, the areas of excess logical space are not rendered. This results in leaving a gap on two sides of the containing window where no geometry is rendered.

Notes

DWF reading applications may receive projection information from the execution of URLs. In this case... (TBD WORK-IN-PROGRESS).

Default

By default the projection attribute is set to "normal", which is the equivalent of executing the following opcode:

(Projection normal)

Implementation in WHIP! Versions

See Also

Define Initial View, and Define Extents (TBD)