Talk:Canvas snippets: Difference between revisions

Talk:Canvas snippets (view source)

316 bytes added , 11 April 2015

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20,741

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 # this would need to be changed when using a different image
-var image_width = 310;
+var map_width = 310;
-var image_height = 155;
+var map_height = 155;
-var x_offset = (width-image_width)/2;
+var x_offset = (width-map_width)/2;
-var y_offset = (height-image_height)/2;
+var y_offset = (height-map_height)/2;
+# assuming Mercator projection for now (untested pseudo code)
+var position2Pixels = func(lat, lon) {
+var xpos = (lon+180)*(map_width/360);
+var latRad = lat*math.PI/180;
+var mercN = math.log(math.tan((math.PI/4)+(latRad/2)));
+var ypos= (map_height/2)-(map_width*mercN/(2*math.PI));
+return [xpos+x_offset, ypos+y_offset];
+}
 # create an image child for the texture