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scale.ts
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scale.ts
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import type {
ControlCursorCallback,
TPointerEvent,
Transform,
TransformActionHandler,
} from '../EventTypeDefs';
import type { FabricObject } from '../shapes/Object/FabricObject';
import type { TAxis } from '../typedefs';
import type { Canvas } from '../canvas/Canvas';
import {
findCornerQuadrant,
getLocalPoint,
invertOrigin,
isLocked,
isTransformCentered,
NOT_ALLOWED_CURSOR,
} from './util';
import { wrapWithFireEvent } from './wrapWithFireEvent';
import { wrapWithFixedAnchor } from './wrapWithFixedAnchor';
type ScaleTransform = Transform & {
gestureScale?: number;
signX?: number;
signY?: number;
};
type ScaleBy = TAxis | 'equally' | '' | undefined;
/**
* Inspect event and fabricObject properties to understand if the scaling action
* @param {Event} eventData from the user action
* @param {FabricObject} fabricObject the fabric object about to scale
* @return {Boolean} true if scale is proportional
*/
export function scaleIsProportional(
eventData: TPointerEvent,
fabricObject: FabricObject
): boolean {
const canvas = fabricObject.canvas as Canvas,
uniformIsToggled = eventData[canvas.uniScaleKey!];
return (
(canvas.uniformScaling && !uniformIsToggled) ||
(!canvas.uniformScaling && uniformIsToggled)
);
}
/**
* Inspect fabricObject to understand if the current scaling action is allowed
* @param {FabricObject} fabricObject the fabric object about to scale
* @param {String} by 'x' or 'y' or ''
* @param {Boolean} scaleProportionally true if we are trying to scale proportionally
* @return {Boolean} true if scaling is not allowed at current conditions
*/
export function scalingIsForbidden(
fabricObject: FabricObject,
by: ScaleBy,
scaleProportionally: boolean
) {
const lockX = isLocked(fabricObject, 'lockScalingX'),
lockY = isLocked(fabricObject, 'lockScalingY');
if (lockX && lockY) {
return true;
}
if (!by && (lockX || lockY) && scaleProportionally) {
return true;
}
if (lockX && by === 'x') {
return true;
}
if (lockY && by === 'y') {
return true;
}
return false;
}
const scaleMap = ['e', 'se', 's', 'sw', 'w', 'nw', 'n', 'ne', 'e'];
/**
* return the correct cursor style for the scale action
* @param {Event} eventData the javascript event that is causing the scale
* @param {Control} control the control that is interested in the action
* @param {FabricObject} fabricObject the fabric object that is interested in the action
* @return {String} a valid css string for the cursor
*/
export const scaleCursorStyleHandler: ControlCursorCallback = (
eventData,
control,
fabricObject
) => {
const scaleProportionally = scaleIsProportional(eventData, fabricObject),
by =
control.x !== 0 && control.y === 0
? 'x'
: control.x === 0 && control.y !== 0
? 'y'
: '';
if (scalingIsForbidden(fabricObject, by, scaleProportionally)) {
return NOT_ALLOWED_CURSOR;
}
const n = findCornerQuadrant(fabricObject, control);
return `${scaleMap[n]}-resize`;
};
/**
* Basic scaling logic, reused with different constrain for scaling X,Y, freely or equally.
* Needs to be wrapped with `wrapWithFixedAnchor` to be effective
* @param {Event} eventData javascript event that is doing the transform
* @param {Object} transform javascript object containing a series of information around the current transform
* @param {number} x current mouse x position, canvas normalized
* @param {number} y current mouse y position, canvas normalized
* @param {Object} options additional information for scaling
* @param {String} options.by 'x', 'y', 'equally' or '' to indicate type of scaling
* @return {Boolean} true if some change happened
* @private
*/
function scaleObject(
eventData: TPointerEvent,
transform: ScaleTransform,
x: number,
y: number,
options: { by?: ScaleBy } = {}
) {
const target = transform.target,
by = options.by,
scaleProportionally = scaleIsProportional(eventData, target),
forbidScaling = scalingIsForbidden(target, by, scaleProportionally);
let newPoint, scaleX, scaleY, dim, signX, signY;
if (forbidScaling) {
return false;
}
if (transform.gestureScale) {
scaleX = transform.scaleX * transform.gestureScale;
scaleY = transform.scaleY * transform.gestureScale;
} else {
newPoint = getLocalPoint(
transform,
transform.originX,
transform.originY,
x,
y
);
// use of sign: We use sign to detect change of direction of an action. sign usually change when
// we cross the origin point with the mouse. So a scale flip for example. There is an issue when scaling
// by center and scaling using one middle control ( default: mr, mt, ml, mb), the mouse movement can easily
// cross many time the origin point and flip the object. so we need a way to filter out the noise.
// This ternary here should be ok to filter out X scaling when we want Y only and vice versa.
signX = by !== 'y' ? Math.sign(newPoint.x || transform.signX || 1) : 1;
signY = by !== 'x' ? Math.sign(newPoint.y || transform.signY || 1) : 1;
if (!transform.signX) {
transform.signX = signX;
}
if (!transform.signY) {
transform.signY = signY;
}
if (
isLocked(target, 'lockScalingFlip') &&
(transform.signX !== signX || transform.signY !== signY)
) {
return false;
}
dim = target._getTransformedDimensions();
// missing detection of flip and logic to switch the origin
if (scaleProportionally && !by) {
// uniform scaling
const distance = Math.abs(newPoint.x) + Math.abs(newPoint.y),
{ original } = transform,
originalDistance =
Math.abs((dim.x * original.scaleX) / target.scaleX) +
Math.abs((dim.y * original.scaleY) / target.scaleY),
scale = distance / originalDistance;
scaleX = original.scaleX * scale;
scaleY = original.scaleY * scale;
} else {
scaleX = Math.abs((newPoint.x * target.scaleX) / dim.x);
scaleY = Math.abs((newPoint.y * target.scaleY) / dim.y);
}
// if we are scaling by center, we need to double the scale
if (isTransformCentered(transform)) {
scaleX *= 2;
scaleY *= 2;
}
if (transform.signX !== signX && by !== 'y') {
transform.originX = invertOrigin(transform.originX);
scaleX *= -1;
transform.signX = signX;
}
if (transform.signY !== signY && by !== 'x') {
transform.originY = invertOrigin(transform.originY);
scaleY *= -1;
transform.signY = signY;
}
}
// minScale is taken care of in the setter.
const oldScaleX = target.scaleX,
oldScaleY = target.scaleY;
if (!by) {
!isLocked(target, 'lockScalingX') && target.set('scaleX', scaleX);
!isLocked(target, 'lockScalingY') && target.set('scaleY', scaleY);
} else {
// forbidden cases already handled on top here.
by === 'x' && target.set('scaleX', scaleX);
by === 'y' && target.set('scaleY', scaleY);
}
return oldScaleX !== target.scaleX || oldScaleY !== target.scaleY;
}
/**
* Generic scaling logic, to scale from corners either equally or freely.
* Needs to be wrapped with `wrapWithFixedAnchor` to be effective
* @param {Event} eventData javascript event that is doing the transform
* @param {Object} transform javascript object containing a series of information around the current transform
* @param {number} x current mouse x position, canvas normalized
* @param {number} y current mouse y position, canvas normalized
* @return {Boolean} true if some change happened
*/
export const scaleObjectFromCorner: TransformActionHandler<ScaleTransform> = (
eventData,
transform,
x,
y
) => {
return scaleObject(eventData, transform, x, y);
};
/**
* Scaling logic for the X axis.
* Needs to be wrapped with `wrapWithFixedAnchor` to be effective
* @param {Event} eventData javascript event that is doing the transform
* @param {Object} transform javascript object containing a series of information around the current transform
* @param {number} x current mouse x position, canvas normalized
* @param {number} y current mouse y position, canvas normalized
* @return {Boolean} true if some change happened
*/
const scaleObjectX: TransformActionHandler<ScaleTransform> = (
eventData,
transform,
x,
y
) => {
return scaleObject(eventData, transform, x, y, { by: 'x' });
};
/**
* Scaling logic for the Y axis.
* Needs to be wrapped with `wrapWithFixedAnchor` to be effective
* @param {Event} eventData javascript event that is doing the transform
* @param {Object} transform javascript object containing a series of information around the current transform
* @param {number} x current mouse x position, canvas normalized
* @param {number} y current mouse y position, canvas normalized
* @return {Boolean} true if some change happened
*/
const scaleObjectY: TransformActionHandler<ScaleTransform> = (
eventData,
transform,
x,
y
) => {
return scaleObject(eventData, transform, x, y, { by: 'y' });
};
export const scalingEqually = wrapWithFireEvent(
'scaling',
wrapWithFixedAnchor(scaleObjectFromCorner)
);
export const scalingX = wrapWithFireEvent(
'scaling',
wrapWithFixedAnchor(scaleObjectX)
);
export const scalingY = wrapWithFireEvent(
'scaling',
wrapWithFixedAnchor(scaleObjectY)
);