Mercurial > hg > orthanc-stone
diff OrthancStone/Resources/Documentation/Coordinates.txt @ 1796:20a0aba0ede5
creation of AnnotationsOverlay
author | Sebastien Jodogne <s.jodogne@gmail.com> |
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date | Wed, 19 May 2021 18:59:45 +0200 |
parents | 9ab251c03eda |
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--- a/OrthancStone/Resources/Documentation/Coordinates.txt Tue May 18 09:57:14 2021 +0200 +++ b/OrthancStone/Resources/Documentation/Coordinates.txt Wed May 19 18:59:45 2021 +0200 @@ -2,6 +2,38 @@ Some notes about the coordinate systems ======================================= +Different systems +----------------- + +* "World" coordinates refer to (x,y,z) positions, typically expressed + in millimeters (according to the DICOM conventions), which allows to + define volumes and 3D cutting planes. + + As explained below, those coordinates actually correspond to + "patient" coordinates if rendering DICOM images. + + The "world" coordinates are *not* used by the Stone Web viewer, + because the latter is a 2D application. + +* "Scene" coordinates refer to (x,y) positions, typically expressed in + millimeters (as a byproduct of world coordinates), which allows to + define the 2D geometric elements that are part of the scene, and + Y-axis pointing downward. + +* "Canvas" coordinates refer to (x,y) subpixel positions that will be + blitted by a compositor onto a drawing canvas. The units are + floating-point pixels, with (0,0) corresponding to the center of the + display surface, and Y-axis pointing downward. The "canvas" + coordinates modify the "scene" coordinates according the zoom/pan + specified by the user. + +* "Pixels" coordinates refer to standard integer (x,y) coordinates of + the surface in memory. (0,0) is the top-left pixel. + + +Relations between 2D and 3D +--------------------------- + * The 3D coordinates are expressed in the PATIENT system, *not* the "gantry" coordinates. As a consequence, the tags "Image Position Patient" (0020,0032) and "Image Orientation Patient" (0020,0037)