canvas 文字换行

/*
        str:要绘制的字符串
        canvas:canvas对象
        initX:绘制字符串起始x坐标
        initY:绘制字符串起始y坐标
        lineHeight:字行高
        */
        canvasTextAutoLine(str, ctx, initX, initY, lineHeight = 32) {
            var lineWidth = 0;
            var canvasWidth = 360;
            var lastSubStrIndex = 0;
            for (let i = 0; i < str.length; i++) {
                lineWidth += ctx.measureText(str[i]).width;
                if (lineWidth > canvasWidth - initX) {
                    ctx.fillText(str.substring(lastSubStrIndex, i), initX, initY);
                    initY += lineHeight;
                    lineWidth = 0;
                    lastSubStrIndex = i;
                }
                if (i == str.length - 1) {
                    ctx.fillText(str.substring(lastSubStrIndex, i + 1), initX, initY);
                }
            }
        },