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comparison doodle/tk/screen_model.d @ 81:d92b9f04b1e8

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Bed time
author "David Bryant <bagnose@gmail.com>"
date Mon, 16 Aug 2010 00:04:27 +0930
parents doodle/tk/pixel_model.d@535bae7a7305
children 100dd23c7bdf
comparison
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80:b759414d2b72 81:d92b9f04b1e8
1 module doodle.tk.screen_model;
2
3 public {
4 import doodle.tk.geometry;
5 }
6
7 private {
8 import doodle.core.misc;
9 }
10
11 // This class manages the relationship between screen space and model space.
12 // Screen is defined as the current window/viewport into the model
13 // It provides convenient high-level operations.
14 //
15 // x and y run right and up respectively for screen and model space
16
17 class ScreenModel {
18 this(in double zoom, in Rectangle canvasBoundsModel, in Rectangle viewBoundsScreen) {
19 _zoom = zoom;
20 _viewBoundsScreen = viewBoundsScreen;
21 _canvasBoundsModel = canvasBoundsModel;
22
23 // Choose the centre of the canvas as the centre of the view
24 _viewCentreModel = _canvasBoundsModel.centre;
25 }
26
27 void consolidateCanvasBounds(in Rectangle requiredCanvasBounds) { _canvasBoundsModel = screenToModel(_viewBoundsScreen) | requiredCanvasBounds; }
28 void canvasAccommodate(in Rectangle bounds) { _canvasBoundsModel = _canvasBoundsModel | bounds; }
29
30 void zoomRelative(in double factor, in Point screenDatum) {
31 // Work out screen distance from current centre to datum,
32 // Do the zoom, then work out the new centre that keeps the
33 // screen distance the same
34
35 Point oldModelDatum = screenToModel(screenDatum);
36 Vector screenDistance = modelToScreen(oldModelDatum - _viewCentreModel);
37 _zoom = clampZoom(zoom * factor);
38 _viewCentreModel = oldModelDatum - screenToModel(screenDistance);
39 }
40
41 void panRelativeScreen(in Vector screenDisplacement) { _viewCentreModel = _viewCentreModel + screenToModel(screenDisplacement); }
42 void panRelativeModel(in Vector modelDisplacement) { _viewCentreModel = _viewCentreModel + modelDisplacement; }
43
44 // For userZoom 1.0 -> 100% means the presentation on the screen is one-to-one with real-life
45 double userZoom(in double pixelsPerMillimetre) const { return _zoom / pixelsPerMillimetre; }
46 double zoom() const { return _zoom; }
47 Rectangle viewBoundsScreen() const { return _viewBoundsScreen; }
48 Rectangle viewBoundsModel() const { return screenToModel(_viewBoundsScreen); }
49 Rectangle canvasBoundsModel() const { return _canvasBoundsModel; }
50 Rectangle canvasBoundsScreen() const { return modelToScreen(_canvasBoundsModel); }
51
52 Point modelToScreen(in Point model) const { return _viewBoundsScreen.centre + _zoom * (model - _viewCentreModel); }
53 Point screenToModel(in Point screen) const { return _viewCentreModel + (screen - _viewBoundsScreen.centre) / _zoom; }
54 Vector modelToScreen(in Vector model) const { return _zoom * model; }
55 Vector screenToModel(in Vector screen) const { return screen / _zoom; }
56 Rectangle modelToScreen(in Rectangle model) const { return Rectangle(modelToScreen(model.position), modelToScreen(model.size)); }
57 Rectangle screenToModel(in Rectangle model) const { return Rectangle(screenToModel(model.position), screenToModel(model.size)); }
58
59 private {
60 static double clampZoom(in double zoom) { return clamp(zoom, 1e-1, 1e2); }
61
62 // Screen units are pixels
63 // Model units are millimetres
64 double _zoom; // pixels-per-millimetre
65 Rectangle _viewBoundsScreen; // bounds of the viewport in screen space
66 Point _viewCentreModel; // where in the model is the centre of our screen
67 Rectangle _canvasBoundsModel; // the bounds of the canvas in model space
68 }
69 }