Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 | import { glMatrix, vec3 } from 'gl-matrix';
import type { IVolumeViewport } from '../types';
import { transformCanvasToIJK } from './transformCanvasToIJK';
/**
* Get the image data for the current slice rendered on the viewport. The image
* data returned is the full slice and not only the region that is visible on
* the viewport. It does not work for oblique views.
* @param viewport - Volume viewport
* @returns Slice image data and matrices to convert from volume
* to slice and vice-versa
*/
function getCurrentVolumeViewportSlice(viewport: IVolumeViewport) {
const { width: canvasWidth, height: canvasHeight } = viewport.getCanvas();
const { sliceToIndexMatrix, indexToSliceMatrix } =
viewport.getSliceViewInfo();
// Get three points from the canvas to help us identify the orientation of
// the slice. Using canvas width/height to get point far away for each other
// because points such as (0,0), (1,0) and (0,1) may be converted to the same
// ijk index when the image is zoomed in.
const ijkOriginPoint = transformCanvasToIJK(viewport, [0, 0]);
const ijkRowPoint = transformCanvasToIJK(viewport, [canvasWidth - 1, 0]);
const ijkColPoint = transformCanvasToIJK(viewport, [0, canvasHeight - 1]);
// Subtract the points to get the row and column vectors in index space
const ijkRowVec = vec3.sub(vec3.create(), ijkRowPoint, ijkOriginPoint);
const ijkColVec = vec3.sub(vec3.create(), ijkColPoint, ijkOriginPoint);
const ijkSliceVec = vec3.cross(vec3.create(), ijkRowVec, ijkColVec);
vec3.normalize(ijkRowVec, ijkRowVec);
vec3.normalize(ijkColVec, ijkColVec);
vec3.normalize(ijkSliceVec, ijkSliceVec);
// Any unit vector parallel to IJK have one component equal to 1 and
// the other two components equal to 0. If two of them are parallel
// the third one is also parallel
const maxIJKRowVec = Math.max(
Math.abs(ijkRowVec[0]),
Math.abs(ijkRowVec[1]),
Math.abs(ijkRowVec[2])
);
const maxIJKColVec = Math.max(
Math.abs(ijkColVec[0]),
Math.abs(ijkColVec[1]),
Math.abs(ijkColVec[2])
);
// Using glMatrix.equals() because the number may be not exactly equal to
// 1 due to rounding issues
if (!glMatrix.equals(1, maxIJKRowVec) || !glMatrix.equals(1, maxIJKColVec)) {
throw new Error('Livewire is not available for rotate/oblique viewports');
}
const { voxelManager } = viewport.getImageData();
const sliceViewInfo = viewport.getSliceViewInfo();
const scalarData = voxelManager.getSliceData(sliceViewInfo);
return {
width: sliceViewInfo.width,
height: sliceViewInfo.height,
scalarData,
sliceToIndexMatrix,
indexToSliceMatrix,
};
}
export {
getCurrentVolumeViewportSlice as default,
getCurrentVolumeViewportSlice,
};
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