[cad-linux-dev] image and viewport entities
- From: Eric Wilhelm <ewilhelm@xxxxxxxxxxxxx>
- To: cad-linux-dev@xxxxxxxxxxxxx
- Date: Fri, 27 Aug 2004 08:04:44 -0500
Anyone have any thoughts on these? I've been working with image
entities in dwg files for a couple years now, so I can attest that
the mixing of a local right-handed coordinate system with a global
left-handed system is an absolute pain.
Clipping is my main concern here. How should viewports and images be
clipped? Using an invisible entity? I could see possibly an
un-named layer or something (somehow the layer is a child of the
viewport or image?)
If you want to clip to a circle, you just refer to the circle.
The other option is that the viewport or images has one "clip_entity:"
slot where we nest some entity data-structure (e.g. circle, arc,
etc.) That frees-up the issue about an entity not on a layer, etc.
without having to use an entirely new syntax to express the clipping.
--- # ./<ID>.yml # viewport entity
ID: integer
points:
- # bottom-left corner
- float # x
- float # y
- float # z (optional)
- # top-right corner
- float # x
- float # y
- float # z (optional)
type: "viewport"
layer: layer_ID
clip:
points:
-
- float # x
- float # y
- float # z (optional)
-
- float # x
- float # y
- float # z (optional)
...
type: "polyline"
closed: boolean
color: [hex, "style"]
object_style: object_style_ID
linetype: [linetype_ID, "style"]
So you just take whatever entity is clipping, but without the
layer/style/color/linetype info and plug it in.
BTW, the viewport needs more info (what is it viewing.) Is using a
rectangle for viewports/images okay? Another option is using one
point, plus rotation and size (height/width) values.
--Eric
--
A counterintuitive sansevieria trifasciata was once literalized
guiltily.
--Product of Artificial Intelligence
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