163     let startX = this.points!.startX!;
185 …      line.slice(this.getCurrentLineBackSize(line, startX - x, true)) + (endX < x + w ? '\n' : '');
188               this.getCurrentLineBackSize(line, startX - x, true),
202   forwardSelected(startX: number, startY: number, endX: number, endY: number): void {
210       this.shellCanvasCtx!.fillRect(startX, startY, endX - startX, endY - startY);
211       startPointX = startX;
220 …       this.shellCanvasCtx!.fillRect(startX, startY, this.shellCanvas!.width - startX, index * 16);
221           startPointX = startX;
244     this.points = { startX: startPointX, startY: startPointY, endX: endPointX, endY: endPointY };
266   reverseSelected(startX: number, startY: number, endX: number, endY: number): void {
274       this.shellCanvasCtx!.fillRect(endX, endY, startX - endX, startY - endY);
277       endPointX = startX;
284 …this.shellCanvasCtx!.fillRect(SpWebHdcShell.LEFT_OFFSET, startY - 16, startX - SpWebHdcShell.LEFT_…
285           endPointX = startX;
298     this.points = { startX: startPointX, startY: startPointY, endX: endPointX, endY: endPointY };
582     let startX: number;  variable
592       startX = event.offsetX;
610         that.forwardSelected(startX, startY, endX, endY);
613         that.reverseSelected(startX, startY, endX, endY);
644   startX: number | undefined;  property in Point