Files
aida_front/src/component/Canvas/CanvasEditor/utils/helperLine.js
2026-01-02 11:24:11 +08:00

445 lines
15 KiB
JavaScript

/**
* Should objects be aligned by a bounding box?
* [Bug] Scaled objects sometimes can not be aligned by edges
*
*/
function initAligningGuidelines(canvas) {
var ctx = canvas.getSelectionContext(),
aligningLineOffset = 1,
aligningLineMargin = 1,
aligningLineWidth = 1,
aligningLineColor = "rgb(0,255,0)",
viewportTransform,
zoom = 1;
function drawVerticalLine(coords) {
drawLine(
coords.x,
coords.y1 > coords.y2 ? coords.y2 : coords.y1,
coords.x,
coords.y2 > coords.y1 ? coords.y2 : coords.y1
);
}
function drawHorizontalLine(coords) {
drawLine(
coords.x1 > coords.x2 ? coords.x2 : coords.x1,
coords.y,
coords.x2 > coords.x1 ? coords.x2 : coords.x1,
coords.y
);
}
function drawLine(x1, y1, x2, y2) {
ctx.save();
ctx.lineWidth = aligningLineWidth;
ctx.strokeStyle = aligningLineColor;
ctx.beginPath();
ctx.moveTo(x1 * zoom + viewportTransform[4], y1 * zoom + viewportTransform[5]);
ctx.lineTo(x2 * zoom + viewportTransform[4], y2 * zoom + viewportTransform[5]);
ctx.stroke();
ctx.restore();
}
function isInRange(value1, value2) {
value1 = Math.round(value1);
value2 = Math.round(value2);
for (var i = value1 - aligningLineMargin, len = value1 + aligningLineMargin; i <= len; i++) {
if (i === value2) {
return true;
}
}
return false;
}
var verticalLines = [],
horizontalLines = [];
canvas.on("mouse:down", function () {
viewportTransform = canvas.viewportTransform;
zoom = canvas.getZoom();
});
canvas.on("object:moving", function (e) {
var activeObject = e.target,
canvasObjects = canvas.getObjects(),
activeObjectCenter = activeObject.getCenterPoint(),
activeObjectLeft = activeObjectCenter.x,
activeObjectTop = activeObjectCenter.y,
activeObjectBoundingRect = activeObject.getBoundingRect(),
activeObjectHeight = activeObjectBoundingRect.height / viewportTransform[3],
activeObjectWidth = activeObjectBoundingRect.width / viewportTransform[0],
horizontalInTheRange = false,
verticalInTheRange = false,
transform = canvas._currentTransform;
if (!transform) return;
// It should be trivial to DRY this up by encapsulating (repeating) creation of x1, x2, y1, and y2 into functions,
// but we're not doing it here for perf. reasons -- as this a function that's invoked on every mouse move
for (var i = canvasObjects.length; i--; ) {
if (canvasObjects[i] === activeObject) continue;
var objectCenter = canvasObjects[i].getCenterPoint(),
objectLeft = objectCenter.x,
objectTop = objectCenter.y,
objectBoundingRect = canvasObjects[i].getBoundingRect(),
objectHeight = objectBoundingRect.height / viewportTransform[3],
objectWidth = objectBoundingRect.width / viewportTransform[0];
// snaps if the right side of the active object touches the left side of the object
if (isInRange(activeObjectLeft + activeObjectWidth / 2, objectLeft - objectWidth / 2)) {
verticalInTheRange = true;
verticalLines.push({
x: objectLeft - objectWidth / 2,
y1:
objectTop < activeObjectTop
? objectTop - objectHeight / 2 - aligningLineOffset
: objectTop + objectHeight / 2 + aligningLineOffset,
y2:
activeObjectTop > objectTop
? activeObjectTop + activeObjectHeight / 2 + aligningLineOffset
: activeObjectTop - activeObjectHeight / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(objectLeft - objectWidth / 2 - activeObjectWidth / 2, activeObjectTop),
"center",
"center"
);
}
// snaps if the left side of the active object touches the right side of the object
if (isInRange(activeObjectLeft - activeObjectWidth / 2, objectLeft + objectWidth / 2)) {
verticalInTheRange = true;
verticalLines.push({
x: objectLeft + objectWidth / 2,
y1:
objectTop < activeObjectTop
? objectTop - objectHeight / 2 - aligningLineOffset
: objectTop + objectHeight / 2 + aligningLineOffset,
y2:
activeObjectTop > objectTop
? activeObjectTop + activeObjectHeight / 2 + aligningLineOffset
: activeObjectTop - activeObjectHeight / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(objectLeft + objectWidth / 2 + activeObjectWidth / 2, activeObjectTop),
"center",
"center"
);
}
// snaps if the bottom of the object touches the top of the active object
if (isInRange(objectTop + objectHeight / 2, activeObjectTop - activeObjectHeight / 2)) {
horizontalInTheRange = true;
horizontalLines.push({
y: objectTop + objectHeight / 2,
x1:
objectLeft < activeObjectLeft
? objectLeft - objectWidth / 2 - aligningLineOffset
: objectLeft + objectWidth / 2 + aligningLineOffset,
x2:
activeObjectLeft > objectLeft
? activeObjectLeft + activeObjectWidth / 2 + aligningLineOffset
: activeObjectLeft - activeObjectWidth / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(activeObjectLeft, objectTop + objectHeight / 2 + activeObjectHeight / 2),
"center",
"center"
);
}
// snaps if the top of the object touches the bottom of the active object
if (isInRange(objectTop - objectHeight / 2, activeObjectTop + activeObjectHeight / 2)) {
horizontalInTheRange = true;
horizontalLines.push({
y: objectTop - objectHeight / 2,
x1:
objectLeft < activeObjectLeft
? objectLeft - objectWidth / 2 - aligningLineOffset
: objectLeft + objectWidth / 2 + aligningLineOffset,
x2:
activeObjectLeft > objectLeft
? activeObjectLeft + activeObjectWidth / 2 + aligningLineOffset
: activeObjectLeft - activeObjectWidth / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(activeObjectLeft, objectTop - objectHeight / 2 - activeObjectHeight / 2),
"center",
"center"
);
}
// snap by the horizontal center line
if (isInRange(objectLeft, activeObjectLeft)) {
verticalInTheRange = true;
verticalLines.push({
x: objectLeft,
y1:
objectTop < activeObjectTop
? objectTop - objectHeight / 2 - aligningLineOffset
: objectTop + objectHeight / 2 + aligningLineOffset,
y2:
activeObjectTop > objectTop
? activeObjectTop + activeObjectHeight / 2 + aligningLineOffset
: activeObjectTop - activeObjectHeight / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(objectLeft, activeObjectTop),
"center",
"center"
);
}
// snap by the left edge
if (isInRange(objectLeft - objectWidth / 2, activeObjectLeft - activeObjectWidth / 2)) {
verticalInTheRange = true;
verticalLines.push({
x: objectLeft - objectWidth / 2,
y1:
objectTop < activeObjectTop
? objectTop - objectHeight / 2 - aligningLineOffset
: objectTop + objectHeight / 2 + aligningLineOffset,
y2:
activeObjectTop > objectTop
? activeObjectTop + activeObjectHeight / 2 + aligningLineOffset
: activeObjectTop - activeObjectHeight / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(objectLeft - objectWidth / 2 + activeObjectWidth / 2, activeObjectTop),
"center",
"center"
);
}
// snap by the right edge
if (isInRange(objectLeft + objectWidth / 2, activeObjectLeft + activeObjectWidth / 2)) {
verticalInTheRange = true;
verticalLines.push({
x: objectLeft + objectWidth / 2,
y1:
objectTop < activeObjectTop
? objectTop - objectHeight / 2 - aligningLineOffset
: objectTop + objectHeight / 2 + aligningLineOffset,
y2:
activeObjectTop > objectTop
? activeObjectTop + activeObjectHeight / 2 + aligningLineOffset
: activeObjectTop - activeObjectHeight / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(objectLeft + objectWidth / 2 - activeObjectWidth / 2, activeObjectTop),
"center",
"center"
);
}
// snap by the vertical center line
if (isInRange(objectTop, activeObjectTop)) {
horizontalInTheRange = true;
horizontalLines.push({
y: objectTop,
x1:
objectLeft < activeObjectLeft
? objectLeft - objectWidth / 2 - aligningLineOffset
: objectLeft + objectWidth / 2 + aligningLineOffset,
x2:
activeObjectLeft > objectLeft
? activeObjectLeft + activeObjectWidth / 2 + aligningLineOffset
: activeObjectLeft - activeObjectWidth / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(activeObjectLeft, objectTop),
"center",
"center"
);
}
// snap by the top edge
if (isInRange(objectTop - objectHeight / 2, activeObjectTop - activeObjectHeight / 2)) {
horizontalInTheRange = true;
horizontalLines.push({
y: objectTop - objectHeight / 2,
x1:
objectLeft < activeObjectLeft
? objectLeft - objectWidth / 2 - aligningLineOffset
: objectLeft + objectWidth / 2 + aligningLineOffset,
x2:
activeObjectLeft > objectLeft
? activeObjectLeft + activeObjectWidth / 2 + aligningLineOffset
: activeObjectLeft - activeObjectWidth / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(activeObjectLeft, objectTop - objectHeight / 2 + activeObjectHeight / 2),
"center",
"center"
);
}
// snap by the bottom edge
if (isInRange(objectTop + objectHeight / 2, activeObjectTop + activeObjectHeight / 2)) {
horizontalInTheRange = true;
horizontalLines.push({
y: objectTop + objectHeight / 2,
x1:
objectLeft < activeObjectLeft
? objectLeft - objectWidth / 2 - aligningLineOffset
: objectLeft + objectWidth / 2 + aligningLineOffset,
x2:
activeObjectLeft > objectLeft
? activeObjectLeft + activeObjectWidth / 2 + aligningLineOffset
: activeObjectLeft - activeObjectWidth / 2 - aligningLineOffset,
});
activeObject.setPositionByOrigin(
new fabric.Point(activeObjectLeft, objectTop + objectHeight / 2 - activeObjectHeight / 2),
"center",
"center"
);
}
}
if (!horizontalInTheRange) {
horizontalLines.length = 0;
}
if (!verticalInTheRange) {
verticalLines.length = 0;
}
});
canvas.on("before:render", function () {
if (canvas.contextTop) {
canvas.clearContext(canvas.contextTop);
}
});
canvas.on("after:render", function () {
for (var i = verticalLines.length; i--; ) {
drawVerticalLine(verticalLines[i]);
}
for (let i = horizontalLines.length; i--; ) {
drawHorizontalLine(horizontalLines[i]);
}
verticalLines.length = horizontalLines.length = 0;
});
canvas.on("mouse:up", function () {
verticalLines.length = horizontalLines.length = 0;
canvas.renderAll();
});
}
export default initAligningGuidelines;
/**
* Augments canvas by assigning to `onObjectMove` and `onAfterRender`.
* This kind of sucks because other code using those methods will stop functioning.
* Need to fix it by replacing callbacks with pub/sub kind of subscription model.
* (or maybe use existing fabric.util.fire/observe (if it won't be too slow))
*/
export function initCenteringGuidelines(canvas) {
var canvasWidth = canvas.getWidth(),
canvasHeight = canvas.getHeight(),
canvasWidthCenter = canvasWidth / 2,
canvasHeightCenter = canvasHeight / 2,
canvasWidthCenterMap = {},
canvasHeightCenterMap = {},
centerLineMargin = 1,
centerLineColor = "rgba(255,0,241,0.5)",
centerLineWidth = 1,
ctx = canvas.getSelectionContext(),
viewportTransform;
for (
var i = canvasWidthCenter - centerLineMargin, len = canvasWidthCenter + centerLineMargin;
i <= len;
i++
) {
canvasWidthCenterMap[Math.round(i)] = true;
}
for (
let i = canvasHeightCenter - centerLineMargin, len = canvasHeightCenter + centerLineMargin;
i <= len;
i++
) {
canvasHeightCenterMap[Math.round(i)] = true;
}
function showVerticalCenterLine() {
showCenterLine(canvasWidthCenter + 0.5, 0, canvasWidthCenter + 0.5, canvasHeight);
}
function showHorizontalCenterLine() {
showCenterLine(0, canvasHeightCenter + 0.5, canvasWidth, canvasHeightCenter + 0.5);
}
function showCenterLine(x1, y1, x2, y2) {
ctx.save();
ctx.strokeStyle = centerLineColor;
ctx.lineWidth = centerLineWidth;
ctx.beginPath();
ctx.moveTo(x1 * viewportTransform[0], y1 * viewportTransform[3]);
ctx.lineTo(x2 * viewportTransform[0], y2 * viewportTransform[3]);
ctx.stroke();
ctx.restore();
}
var afterRenderActions = [],
isInVerticalCenter,
isInHorizontalCenter;
canvas.on("mouse:down", function () {
viewportTransform = canvas.viewportTransform;
});
canvas.on("object:moving", function (e) {
var object = e.target,
objectCenter = object.getCenterPoint(),
transform = canvas._currentTransform;
if (!transform) return;
((isInVerticalCenter = Math.round(objectCenter.x) in canvasWidthCenterMap),
(isInHorizontalCenter = Math.round(objectCenter.y) in canvasHeightCenterMap));
if (isInHorizontalCenter || isInVerticalCenter) {
object.setPositionByOrigin(
new fabric.Point(
isInVerticalCenter ? canvasWidthCenter : objectCenter.x,
isInHorizontalCenter ? canvasHeightCenter : objectCenter.y
),
"center",
"center"
);
}
});
canvas.on("before:render", function () {
if (canvas.contextTop) {
canvas.clearContext(canvas.contextTop);
}
});
canvas.on("after:render", function () {
if (isInVerticalCenter) {
showVerticalCenterLine();
}
if (isInHorizontalCenter) {
showHorizontalCenterLine();
}
});
canvas.on("mouse:up", function () {
// clear these values, to stop drawing guidelines once mouse is up
isInVerticalCenter = isInHorizontalCenter = null;
canvas.renderAll();
});
}