Usage:

• label= parameter adds text on a transparent background at point x1,y1, using label-color, label-size, label-angle, label-pos=left/right/top/bottom.
• shape=circle, square, diamond, triangle are equel width centered on x1,y1, and use mark-size.
• box, ellipse,itriangle allow mark-size=w,h to set width and height. A third number for box sets corner-radius.
• shape=panel has its top-left corner at x1,y1, places text within rather than beside the shape, and uses mark-size, border-radius, shape-angle.
• shape=image, uses the value in 'mark' or default red pog. Set mark-size. Height may be needed to align labels correctly, but doesn't affect the image itself.
• A 'photo-panel' option creates a 'standard' 50px high panel, adds a photo to left or right. A width dimension is needed to match the panel edge)
• All shapes can also set shape-color and optional opacity, and a shape-outline parameter to set color, width, opacity, style of an outline
• Shapes can also have auto- or manual-numbers to give a sequence of numbered shapes.
• Labels can optionally have a line to connect to their shape, as can shape-numbers if the shapes are congested.
• label-size can optionally include a plain background and/or 1px black outline around the label. eg label-size=12,outline,background