rotate the map to face direction of travel

there is a bit of smoothing so it does not instantly lurch to the
new new course, as the visual effect was quite jarring
This commit is contained in:
Daniel Barlow 2025-06-08 17:59:46 +01:00
parent 8c51113d6e
commit 8ec64bb1b0

View File

@ -65,7 +65,8 @@ label.readout {
:lat 49
:lon 0
:zoom 17
:course 22
:course 0
:smooth-course 0
}
)
@ -253,6 +254,10 @@ label.readout {
bounds.pixels.y)
(draw-onto-map-surface bounds app-state.zoom)))))
(g:translate (+ (/ viewport-width 2)) (+ (/ viewport-height 2)))
(g:rotate (* (/ (- 360 app-state.smooth-course) 180) math.pi))
(g:translate (- (/ viewport-width 2)) (- (/ viewport-height 2)))
(g:set_source_surface map-surface (- offset-x) (- offset-y))
(g:set_operator cairo.Operator.SOURCE)
(g:rectangle 0 0 viewport-width viewport-height)
@ -293,9 +298,6 @@ label.readout {
(expect= (hhmmss (+ 45 (* 60 12) (* 60 60 3))) "3:12:45")
(fn update-app-state [new-vals]
(let [old-bounds
(map-bounds app-state.lat app-state.lon app-state.zoom)]
@ -306,6 +308,9 @@ label.readout {
(not (= old-bounds.min.x bounds.min.x))
(not (= old-bounds.min.y bounds.min.y)))
(set map-surface nil)))
(set app-state.smooth-course
(+ app-state.smooth-course
(* 0.05 (- app-state.course app-state.smooth-course))))
(each [name widget (pairs state-widgets)]
(case name
:speed (widget:set_label
@ -340,7 +345,8 @@ label.readout {
(fn [self g]
(g:set_source_rgb 0.4 0.0 0.1)
(g:translate (// height 2) (// height 2))
(g:rotate (* (/ app-state.course 180) math.pi))
(g:rotate (* (/ (- app-state.course app-state.smooth-course)
180) math.pi))
(g:translate (// height -2) (// height -2))
(g:set_line_width 4)
(g:move_to 10 height)
@ -393,7 +399,11 @@ label.readout {
GLib.PRIORITY_DEFAULT
20 ; ms
(fn []
;; run cqueues scheduler
(cq:step 0)
;; for smoother rotation when course changes, repaint more often than
;; once per gnss message
(update-app-state {})
true)
nil nil)