import {
ClampToEdgeWrapping,
DoubleSide,
LinearFilter,
Mesh,
MeshBasicMaterial,
PlaneGeometry,
Texture,
SRGBColorSpace
} from 'three';
/**
* This class has been made to hold a slice of a volume data
* @class
* @param {Volume} volume The associated volume
* @param {number} [index=0] The index of the slice
* @param {string} [axis='z'] For now only 'x', 'y' or 'z' but later it will change to a normal vector
* @see Volume
*/
class VolumeSlice {
constructor( volume, index, axis ) {
const slice = this;
/**
* @member {Volume} volume The associated volume
*/
this.volume = volume;
/**
* @member {Number} index The index of the slice, if changed, will automatically call updateGeometry at the next repaint
*/
index = index || 0;
Object.defineProperty( this, 'index', {
get: function () {
return index;
},
set: function ( value ) {
index = value;
slice.geometryNeedsUpdate = true;
return index;
}
} );
/**
* @member {String} axis The normal axis
*/
this.axis = axis || 'z';
/**
* @member {HTMLCanvasElement} canvas The final canvas used for the texture
*/
/**
* @member {CanvasRenderingContext2D} ctx Context of the canvas
*/
this.canvas = document.createElement( 'canvas' );
/**
* @member {HTMLCanvasElement} canvasBuffer The intermediary canvas used to paint the data
*/
/**
* @member {CanvasRenderingContext2D} ctxBuffer Context of the canvas buffer
*/
this.canvasBuffer = document.createElement( 'canvas' );
this.updateGeometry();
const canvasMap = new Texture( this.canvas );
canvasMap.minFilter = LinearFilter;
canvasMap.wrapS = canvasMap.wrapT = ClampToEdgeWrapping;
canvasMap.colorSpace = SRGBColorSpace;
const material = new MeshBasicMaterial( { map: canvasMap, side: DoubleSide, transparent: true } );
/**
* @member {Mesh} mesh The mesh ready to get used in the scene
*/
this.mesh = new Mesh( this.geometry, material );
this.mesh.matrixAutoUpdate = false;
/**
* @member {Boolean} geometryNeedsUpdate If set to true, updateGeometry will be triggered at the next repaint
*/
this.geometryNeedsUpdate = true;
this.repaint();
/**
* @member {Number} iLength Width of slice in the original coordinate system, corresponds to the width of the buffer canvas
*/
/**
* @member {Number} jLength Height of slice in the original coordinate system, corresponds to the height of the buffer canvas
*/
/**
* @member {Function} sliceAccess Function that allow the slice to access right data
* @see Volume.extractPerpendicularPlane
* @param {Number} i The first coordinate
* @param {Number} j The second coordinate
* @returns {Number} the index corresponding to the voxel in volume.data of the given position in the slice
*/
}
/**
* @member {Function} repaint Refresh the texture and the geometry if geometryNeedsUpdate is set to true
* @memberof VolumeSlice
*/
repaint() {
if ( this.geometryNeedsUpdate ) {
this.updateGeometry();
}
const iLength = this.iLength,
jLength = this.jLength,
sliceAccess = this.sliceAccess,
volume = this.volume,
canvas = this.canvasBuffer,
ctx = this.ctxBuffer;
// get the imageData and pixel array from the canvas
const imgData = ctx.getImageData( 0, 0, iLength, jLength );
const data = imgData.data;
const volumeData = volume.data;
const upperThreshold = volume.upperThreshold;
const lowerThreshold = volume.lowerThreshold;
const windowLow = volume.windowLow;
const windowHigh = volume.windowHigh;
// manipulate some pixel elements
let pixelCount = 0;
if ( volume.dataType === 'label' ) {
//this part is currently useless but will be used when colortables will be handled
for ( let j = 0; j < jLength; j ++ ) {
for ( let i = 0; i < iLength; i ++ ) {
let label = volumeData[ sliceAccess( i, j ) ];
label = label >= this.colorMap.length ? ( label % this.colorMap.length ) + 1 : label;
const color = this.colorMap[ label ];
data[ 4 * pixelCount ] = ( color >> 24 ) & 0xff;
data[ 4 * pixelCount + 1 ] = ( color >> 16 ) & 0xff;
data[ 4 * pixelCount + 2 ] = ( color >> 8 ) & 0xff;
data[ 4 * pixelCount + 3 ] = color & 0xff;
pixelCount ++;
}
}
} else {
for ( let j = 0; j < jLength; j ++ ) {
for ( let i = 0; i < iLength; i ++ ) {
let value = volumeData[ sliceAccess( i, j ) ];
let alpha = 0xff;
//apply threshold
alpha = upperThreshold >= value ? ( lowerThreshold <= value ? alpha : 0 ) : 0;
//apply window level
value = Math.floor( 255 * ( value - windowLow ) / ( windowHigh - windowLow ) );
value = value > 255 ? 255 : ( value < 0 ? 0 : value | 0 );
data[ 4 * pixelCount ] = value;
data[ 4 * pixelCount + 1 ] = value;
data[ 4 * pixelCount + 2 ] = value;
data[ 4 * pixelCount + 3 ] = alpha;
pixelCount ++;
}
}
}
ctx.putImageData( imgData, 0, 0 );
this.ctx.drawImage( canvas, 0, 0, iLength, jLength, 0, 0, this.canvas.width, this.canvas.height );
this.mesh.material.map.needsUpdate = true;
}
/**
* @member {Function} Refresh the geometry according to axis and index
* @see Volume.extractPerpendicularPlane
* @memberof VolumeSlice
*/
updateGeometry() {
const extracted = this.volume.extractPerpendicularPlane( this.axis, this.index );
this.sliceAccess = extracted.sliceAccess;
this.jLength = extracted.jLength;
this.iLength = extracted.iLength;
this.matrix = extracted.matrix;
this.canvas.width = extracted.planeWidth;
this.canvas.height = extracted.planeHeight;
this.canvasBuffer.width = this.iLength;
this.canvasBuffer.height = this.jLength;
this.ctx = this.canvas.getContext( '2d' );
this.ctxBuffer = this.canvasBuffer.getContext( '2d' );
if ( this.geometry ) this.geometry.dispose(); // dispose existing geometry
this.geometry = new PlaneGeometry( extracted.planeWidth, extracted.planeHeight );
if ( this.mesh ) {
this.mesh.geometry = this.geometry;
//reset mesh matrix
this.mesh.matrix.identity();
this.mesh.applyMatrix4( this.matrix );
}
this.geometryNeedsUpdate = false;
}
}
export { VolumeSlice };
