pixel-editor/js/_rectSelect.js

var isRectSelecting = false;
let startX;
let startY;
let endX;
let endY;

function startRectSelection(mouseEvent) {
	// Putting the vfx layer on top of everything
	VFXCanvas.style.zIndex = MAX_Z_INDEX;

	// Saving the start coords of the rect
	let cursorPos = getCursorPosition(mouseEvent);
	startX = Math.round(cursorPos[0] / zoom) + 0.5;
	startY = Math.round(cursorPos[1] / zoom) + 0.5;

	// Avoiding external selections
	if (startX < 0) {
		startX = 0;
	}
	else if (startX > currentLayer.canvas.width) {
		startX = currentLayer.canvas.width;
	}

	if (startY < 0) {
		startY = 0;
	}
	else if (startY > currentLayer.canvas.height) {
		startY = currentLayer.canvas.height;
	}

	// Drawing the rect
	drawRect(startX, startY);
}

function updateRectSelection(mouseEvent) {
	let pos = getCursorPosition(mouseEvent);
	
	// Drawing the rect
	drawRect(Math.round(pos[0] / zoom) + 0.5, Math.round(pos[1] / zoom) + 0.5);
}

function endRectSelection(mouseEvent) {
	// Getting the end position
	let currentPos = getCursorPosition(mouseEvent);
	endX = Math.round(currentPos[0] / zoom);
	endY = Math.round(currentPos[1] / zoom);

	// Inverting end and start (start must always be the top left corner)
	if (endX < startX) {
		let tmp = endX;
		endX = startX;
		startX = tmp;
	}
	// Same for the y
	if (endY < startY) {
		let tmp = endY;
		endY = startY;
		startY = tmp;
	}

	// Resetting this
	isRectSelecting = false;
	// Getting the selected pixels
	imageDataToMove = currentLayer.context.getImageData(startX, startY, endX - startX, endY - startY);
	
	currentLayer.context.clearRect(startX, startY, endX - startX - 1, endY - startY - 1);
	// Moving those pixels from the current layer to the tmp layer
	TMPLayer.context.putImageData(imageDataToMove, startX, startY);

	// Selecting the move tool
	currentTool = 'moveselection';
	currentToolTemp = currentTool;
	// Updating the cursor 
	updateCursor();

	//currentLayer.context.putImageData(imageData, startX, startY);
}

function drawRect(x, y) {
	console.log("Currently selecting");
	// Getting the vfx context
	let vfxContext = VFXCanvas.getContext("2d");

	// Clearing the vfx canvas
	vfxContext.clearRect(0, 0, VFXCanvas.width, VFXCanvas.height);
	vfxContext.lineWidth = 1;
	vfxContext.strokeStyle = "black";
	vfxContext.setLineDash([4]);

	// Drawing the rect
	vfxContext.beginPath();
	vfxContext.rect(startX, startY, x - startX, y - startY);

	vfxContext.stroke();

	// TODO: make the rect blink from black to white in case of dark backgrounds
}

function applyChanges() {
	VFXCanvas.style.zIndex = MIN_Z_INDEX;
}

// Checks whether the pointer is inside the selected area or not
function cursorInSelectedArea() {
	let cursorPos = getCursorPosition(currentMouseEvent);
	let x = cursorPos[0] / zoom;
	let y = cursorPos[1] / zoom;

	let leftX = Math.min(startX, endX);
	let rightX = Math.max(startX, endX);
	let topY = Math.max(startY, endY);
	let bottomY = Math.min(startY, endY);

	// ISSUE: is it <= or <? test it
	if (leftX <= x && x <= rightX) {
		if (bottomY <= y && y <= topY) {
			return true;
		}

		return false;
	}

	return false;
}

function moveSelection(x, y, width, height) {
	// Getting the vfx context
	let vfxContext = VFXCanvas.getContext("2d");

	// Clearing the vfx canvas
	vfxContext.clearRect(0, 0, VFXCanvas.width, VFXCanvas.height);
	vfxContext.lineWidth = 1;
	vfxContext.setLineDash([4]);

	startX = Math.round(Math.round(x) - Math.round(width / 2)) + 0.5;
	startY = Math.round(Math.round(y) - Math.round(height / 2)) + 0.5;
	endX = startX + Math.round(width);
	endY = startY + Math.round(height);

	// Drawing the rect
	vfxContext.beginPath();
	vfxContext.rect(startX, startY, width, height);

	vfxContext.stroke();
}