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Several changes to improve zooming behaviour. #299

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Merged
natacha-beck merged 2 commits into from
May 13, 2016
Merged

Several changes to improve zooming behaviour. #299

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401af5e
Set a reasonable initial zoom level.
Apr 22, 2016
4c1e83c
More improvements to zooming - sensible cursor drawing at high zoom l…
Apr 25, 2016
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7 changes: 7 additions & 0 deletions examples/volume-viewer-demo.js
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Original file line number Diff line number Diff line change
Expand Up @@ -285,6 +285,13 @@ $(function() {
});
});

$(document).keypress(function(e) {
if (e.keyCode === 114) {
// Reset displays if user presses 'r' key.
viewer.resetDisplays();
viewer.redrawVolumes();
}
});
//////////////////////////////////
// Per volume UI hooks go in here.
//////////////////////////////////
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12 changes: 8 additions & 4 deletions src/brainbrowser/volume-viewer/lib/panel.js
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Expand Up @@ -295,9 +295,10 @@
* ```
*/
reset: function() {
panel.zoom = 1;
panel.zoom = panel.default_zoom;
panel.image_center.x = panel.canvas.width / 2;
panel.image_center.y = panel.canvas.height / 2;
panel.updated = true;
},

/**
Expand Down Expand Up @@ -496,7 +497,10 @@
}

if (panel.volume) {
setSlice(panel, panel.volume.slice(panel.axis));
var volume = panel.volume;
setSlice(panel, volume.slice(panel.axis));
panel.default_zoom = volume.getPreferredZoom(panel.canvas.width, panel.canvas.height);
panel.zoom = panel.default_zoom;
}

return panel;
Expand All @@ -517,7 +521,7 @@
var context = panel.context;
var cursor = panel.getCursorPosition();
var zoom = panel.zoom;
var length = 8 * zoom;
var length = 8 * (zoom / panel.default_zoom);
var x, y, space;
var distance;
var dx, dy;
Expand All @@ -528,7 +532,7 @@
context.strokeStyle = color;
context.fillStyle = color;

space = zoom;
space = 1;
x = cursor.x;
y = cursor.y;

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5 changes: 3 additions & 2 deletions src/brainbrowser/volume-viewer/modules/loading.js
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Expand Up @@ -646,7 +646,7 @@ BrainBrowser.VolumeViewer.modules.loading = function(viewer) {

last_touch_distance = null;
}

canvas.addEventListener("mousedown", function(event) {
event.preventDefault();

Expand Down Expand Up @@ -696,7 +696,8 @@ BrainBrowser.VolumeViewer.modules.loading = function(viewer) {
}

function zoom(delta) {
panel.zoom = Math.max(panel.zoom + delta * 0.05, 0.05);
panel.zoom *= (delta < 0) ? 1/1.05 : 1.05;
panel.zoom = Math.max(panel.zoom, 0.25);
panel.updateVolumePosition();
panel.updateSlice();

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15 changes: 15 additions & 0 deletions src/brainbrowser/volume-viewer/volume-loaders/minc.js
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Expand Up @@ -372,6 +372,21 @@
},
getVoxelMax: function() {
return volume.header.voxel_max;
},
/* given a width and height (from the panel), this function returns the "best"
* single zoom level that will guarantee that the image fits exactly into the
* current panel.
*/
getPreferredZoom: function(width, height) {
var header = volume.header;
var x_fov = header.xspace.space_length * Math.abs(header.xspace.step);
var y_fov = header.yspace.space_length * Math.abs(header.yspace.step);
var z_fov = header.zspace.space_length * Math.abs(header.xspace.step);
var xw = width / x_fov;
var yw = width / y_fov;
var yh = height / y_fov;
var zh = height / z_fov;
return Math.min(yw, xw, zh, yh);
}
};
return volume;
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