Project: svg
Task (challenging): When click label trapezoid, use mouse in canvas to draw a svg polygon trapezoid (fill color is white, line width is '.line-width' value, line color is '.color' value). There is a rect whose left-top is the point when mouse pressing down and right-bottom is the point when mouse pressing up. The trapezoid's left-bottom is the rect left-bottom, right-bottom is the rect right-bottom, left-top and right-top points divide rect top edge to 3 equal parts. Polygon points sequence is left-bottom, right-bottom, top.