No commit message

No commit message

tutorial/t4.geo

@@ -87,9 +87,21 @@ View "comments" {
   T3(0, 0.11, 0, TextAttributes("Align", "Center", "Font", "Helvetica")){ "Hole" };
 
   // If a string starts with `file://', the rest is interpreted as an image
-  // file, whose size and orientation can be specified after a `@' symbol:
-  T3(-0.01, 0.09, 0, 0){ "file://image.png@0.02x0" };
-  T3(-0.01, 0.09, 0, 0){ "file://image.png@0.02x0,0,0,1,0,1,0" };
+  // file. For 3D annotations, the size in model coordinates can be specified
+  // after a `@' symbol in the form `widthxheight' (if one of `width' or
+  // `height' is zero, natural scaling is used; if both are zero, original image
+  // dimensions in pixels are used):
+  T3(0, 0.09, 0, TextAttributes("Align", "Center")){ "file://image.png@0.01x0" };
+
+  // The 3D orientation of the image can be specified by proving the direction
+  // of the bottom and left edge of the image in model space:
+  T3(-0.01, 0.09, 0, 0){ "file://image.png@0.01x0,0,0,1,0,1,0" };
+
+  // The image can also be drawn in "billboard" mode, i.e. always parallel to
+  // the camera, by using the `#' symbol:
+  T3(0, 0.12, 0, TextAttributes("Align", "Center")){ "file://image.png@0.01x0#" };
+
+  // The size of 2D annotations is goven directly in pixels:
   T2(350, -7, 0){ "file://image.png@20x0" };
 };