Here is a program that draws an arrow and annotates it with lines that mark bounding box positions:
#lang racket
(require pict)
(define (metrics-frame p)
(define metrics-line (hline (pict-width p) 0))
(let* ([metrics (rectangle (pict-width p) (pict-height p))]
[metrics (pin-over metrics 0 (pict-ascent p) (colorize metrics-line "red"))]
[metrics (pin-over metrics 0 (- (pict-height p) (pict-descent p))
(linestyle 'long-dash (colorize metrics-line "blue")))])
(pin-over p 0 0 (colorize (linewidth 1/4 metrics) "gray"))))
(define p (metrics-frame (panorama (pin-over (metrics-frame (linewidth 2 (hline 40 2)))
36 -4 (metrics-frame (arrowhead 10 0))))))
(send (pict->bitmap (scale (inset p 2 2 2 5) 10))
save-file "out.png" 'png)This is the program’s output:
The dashed blue line at the very bottom is the descent-specified baseline of the resulting pict. Its position doesn’t make any sense: both of the original picts’ descents are 0. I took a look at the panorama implementation, but I don’t fully understand all the details, especially since pict uses two different coordinate spaces.
Here is a program that draws an arrow and annotates it with lines that mark bounding box positions:
This is the program’s output:
The dashed blue line at the very bottom is the descent-specified baseline of the resulting pict. Its position doesn’t make any sense: both of the original picts’ descents are 0. I took a look at the
panoramaimplementation, but I don’t fully understand all the details, especially since pict uses two different coordinate spaces.