add plot-inset and plot-legend-padding parameters (#124)

... to control the amount of space left unused around the plot edge and plot legend.

plot-doc/plot/scribblings/params.scrbl

@@ -117,6 +117,27 @@ Amount of ambient light, and whether 3D plots are rendered with diffuse and spec
 
 }
 
+@defparam[plot-inset inset (or/c (>=/c 0) (list (>=/c 0) (>=/c 0) (>=/c 0) (>=/c 0))) #:value 0]{
+
+  The amount of space around the plot to leave unused, when calculating plot
+  layouts for ticks and axis labels.  The parameter can be specified as a
+  single value, which applies to all sides of the plot image, or as a list of
+  four separate values for the left, right, top, and bottom margins of the
+  plot image.
+
+  One example use for this parameter is to avoid clipping tick marks when
+  lines for plot elements are very thick, see @racket[plot-line-width] and
+  @racket[line-width]. In such a case, the end of axis ticks can be drawn
+  beyond the end point of the line, and might be clipped at the edge of the
+  drawing region.  A non-zero @racket[plot-inset] value can be used to avoid
+  this clipping.
+
+  See also @racket[plot-legend-padding] for an equivalent setting for the plot
+  legend.
+
+  @history[#:added "8.11"]
+}
+
 @deftogether[((defparam plot-foreground color plot-color/c #:value 0)
               (defparam plot-background color plot-color/c #:value 0))]{
 The plot foreground and background color.
@@ -161,6 +182,26 @@ For example, the value @racket['(columns 1 equal-size)] will place the legend en
 @history[#:added "7.9"]
 }
 
+@defparam[plot-legend-padding padding (or/c (>=/c 0) (list (>=/c 0) (>=/c 0) (>=/c 0) (>=/c 0))) #:value 0]{
+
+  The amount of space to add between the legend entries and the border drawn
+  around the legend.  The parameter can be specified as a single value, which
+  applies to all sides, or as a list of four separate values for the left,
+  right, top, and bottom sides of the legend.
+
+  One example use for this parameter is to avoid clipping thick lines used in
+  legend entries, see @racket[plot-line-width] and @racket[line-width]. In
+  such a case, the end of the lines can be drawn outside the border of the
+  legend, a non-zero @racket[plot-legend-padding] value can be used to avoid
+  this situation.
+
+  See also @racket[plot-inset] for a similar setting for the entire plot
+  image.
+
+  @history[#:added "8.11"]
+}
+
+
 @defparam[plot-tick-size size (>=/c 0) #:value 10]{
 The length of tick lines, in drawing units.
 }

plot-lib/plot/private/common/parameter-groups.rkt

@@ -42,7 +42,9 @@
      arrow-head-size-or-scale
      arrow-head-angle
      plot-line-cap
-     line-cap))
+     line-cap
+     plot-inset
+     plot-legend-padding))
 
   (define-parameter-group plot3d-appearance
     (plot3d-samples
@@ -114,7 +116,9 @@
       (U (List '= Nonnegative-Real) Nonnegative-Real)
       Nonnegative-Real
       Plot-Pen-Cap
-      Plot-Pen-Cap)
+      Plot-Pen-Cap
+      (U Nonnegative-Real (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))
+      (U Nonnegative-Real (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real)))
      ;;plot3d-appearance
      (List Positive-Integer Real Real Nonnegative-Real Boolean Boolean)
      ;;plot-labels

plot-lib/plot/private/common/parameters.rkt

@@ -79,6 +79,13 @@
 (defparam plot-legend-anchor anchor Legend-Anchor 'top-left)
 (defparam plot-legend-layout layout Legend-Layout '(columns 1 equal-size))
 (defparam2 plot-legend-box-alpha alpha Real Nonnegative-Real 2/3 (unit-ivl 'plot-legend-box-alpha))
+(defparam plot-legend-padding
+  (U
+   ;; A single padding value for all sides
+   Nonnegative-Real
+   ;; Separate left, right, top, and bottom padding values
+   (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))
+  0.0)
 (defparam plot-animating? Boolean #f)
 
 (defparam plot-x-axis? Boolean #t)
@@ -108,7 +115,13 @@
 (defparam plot-y-far-tick-label-anchor anchor Anchor 'left)
 
 (defparam plot-decorations? Boolean #t)
-
+(defparam plot-inset
+  (U
+   ;; A single inset value for all sides
+   Nonnegative-Real
+   ;; Separate left, right, top, and bottom inset values
+   (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))
+  0.0)
 (defparam plot-pen-color-map (U Symbol #f) #f)
 (defparam plot-brush-color-map (U Symbol #f) #f)
 

plot-lib/plot/private/common/plot-device.rkt

@@ -614,12 +614,17 @@
     ;; the understanding is that Rect will be the complete dc for a legend outside the plot-area
     ;; and the plot-area otherwise
 
-    (: calculate-legend-parameters (-> (Listof legend-entry) Rect Anchor
+    (: calculate-legend-parameters (-> (Listof legend-entry)
+                                       Rect
+                                       Anchor
+                                       (U Nonnegative-Real
+                                          (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))
+
                                        (Values Rect (Listof Exact-Rational)
                                                Nonnegative-Exact-Rational (Listof Real) (Listof Real)
                                                Nonnegative-Exact-Rational (Listof Real)
                                                Boolean Nonnegative-Integer)))
-    (define/private (calculate-legend-parameters legend-entries rect legend-anchor)
+    (define/private (calculate-legend-parameters legend-entries rect anchor padding)
       (define n (length legend-entries))
       (define labels (map legend-entry-label legend-entries))
       (match-define (vector (ivl x-min x-max) (ivl y-min y-max)) rect)
@@ -692,21 +697,28 @@
 
          ;; top-left corner of legend
          (define legend-x-min
-           (case legend-anchor
+           (case anchor
              [(top-left left bottom-left auto)     x-min]
              [(top-right right bottom-right)  (- x-max legend-x-size)]
              [(center bottom top)             (- (* 1/2 (+ x-min x-max))
                                                  (* 1/2 legend-x-size))]))
 
          (define legend-y-min
-           (case legend-anchor
+           (case anchor
              [(top-left top top-right auto)      y-min]
              [(bottom-left bottom bottom-right)  (- y-max legend-y-size)]
              [(center left right)                (- (* 1/2 (+ y-min y-max))
                                                     (* 1/2 legend-y-size))]))
 
-         (define legend-rect (vector (ivl legend-x-min (+ legend-x-min legend-x-size))
-                                     (ivl legend-y-min (+ legend-y-min legend-y-size))))
+         (define legend-rect
+           (let-values ([(pad-left pad-right pad-top pad-bottom)
+                         (if (list? padding)
+                             (values (list-ref padding 0) (list-ref padding 1) (list-ref padding 2) (list-ref padding 3))
+                             (values padding padding padding padding))])
+             (vector (ivl (- legend-x-min pad-left)
+                          (+ legend-x-min legend-x-size pad-right))
+                     (ivl (- legend-y-min pad-top)
+                          (+ legend-y-min legend-y-size pad-bottom)))))
 
          ;; per entry x/y left/top corners
          (define label-x-mins (for/fold ([mins : (Listof Real) (list (+ legend-x-min horiz-gap))]
@@ -732,7 +744,7 @@
         [else
          (raise-argument-error 'draw-legend "rect-known?" 1 legend-entries rect)]))
 
-    (define/public (calculate-legend-rect legend-entries rect legend-anchor)
+    (define/public (calculate-legend-rect legend-entries rect anchor padding)
       ;; Change font for correct size calculation in calculate-legend-parameters
       (define old-size (send (send dc get-font) get-point-size))
       (define old-face (send (send dc get-font) get-face))
@@ -746,7 +758,7 @@
                                   draw-x-size label-x-mins draw-x-mins
                                   draw-y-size label-y-mins
                                   cols? div)
-        (calculate-legend-parameters legend-entries rect legend-anchor))
+        (calculate-legend-parameters legend-entries rect anchor padding))
 
       ;; Undo change font
       (set-font-attribs old-size old-face old-family)
@@ -755,6 +767,7 @@
 
     (define/public (draw-legend legend-entries rect)
       (define legend-anchor (plot-legend-anchor))
+      (define legend-padding (plot-legend-padding))
       (when (not (eq? legend-anchor 'no-legend))
         (match-define (list (legend-entry #{labels : (Listof (U String pict))}
                                           #{draw-procs : (Listof Legend-Draw-Proc)})
@@ -774,7 +787,7 @@
                                     draw-x-size label-x-mins draw-x-mins
                                     draw-y-size label-y-mins
                                     cols? div)
-          (calculate-legend-parameters legend-entries rect (legend-anchor->anchor legend-anchor)))
+          (calculate-legend-parameters legend-entries rect (legend-anchor->anchor legend-anchor) legend-padding))
 
         ;; legend background
         (set-pen (plot-foreground) 1 'transparent)

plot-lib/plot/private/common/types.rkt

@@ -163,7 +163,12 @@
    [draw-arrow-glyph (-> (Vectorof Real) Real Real Void)]
    [draw-glyphs (-> (Listof (Vectorof Real)) Point-Sym Nonnegative-Real Void)]
    [draw-pict (->* [pict (Vectorof Real)] (Anchor Real) Void)]
-   [calculate-legend-rect (-> (Listof legend-entry) Rect Anchor Rect)]
+   [calculate-legend-rect (-> (Listof legend-entry)
+                              Rect
+                              Anchor
+                              (U Nonnegative-Real
+                                 (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))
+                              Rect)]
    [draw-legend (-> (Listof legend-entry) Rect Void)]))
 
 (require "plotmetrics.rkt")

plot-lib/plot/private/plot2d/plot-area.rkt

@@ -257,7 +257,8 @@
                                      legend
                                      (vector (ivl dc-x-min (+ dc-x-min dc-x-size))
                                              (ivl dc-y-min (+ dc-y-min dc-y-size)))
-                                     (legend-anchor->anchor legend-anchor)))]
+                                     (legend-anchor->anchor legend-anchor)
+                                     (plot-legend-padding)))]
              [gap (pen-gap)]
              [make-print
               (λ ([get-bounds : (-> (Listof Real))])
@@ -640,16 +641,23 @@
     (define: right : Real  0)
     (define: top : Real  0)
     (define: bottom : Real  0)
-    (let-values ([(left-val right-val top-val bottom-val)
-                  (margin-fixpoint 0 dc-x-size 0 dc-y-size
-                                   init-left-margin  init-right-margin
-                                   init-top-margin   init-bottom-margin
-                                   (λ ([left : Real] [right : Real] [top : Real] [bottom : Real])
-                                     (get-param-vs/set-view->dc! left right top bottom)))])
-      (set! left left-val)
-      (set! right right-val)
-      (set! top top-val)
-      (set! bottom bottom-val))
+    (let ([inset (plot-inset)])
+      (let-values ([(left-inset right-inset top-inset bottom-inset)
+                    (if (list? inset)
+                        (values (list-ref inset 0) (list-ref inset 1) (list-ref inset 2) (list-ref inset 3))
+                        (values inset inset inset inset))])
+        (let-values ([(left-val right-val top-val bottom-val)
+                      (margin-fixpoint
+                       left-inset        (- dc-x-size right-inset)
+                       top-inset         (- dc-y-size bottom-inset)
+                       init-left-margin  init-right-margin
+                       init-top-margin   init-bottom-margin
+                       (λ ([left : Real] [right : Real] [top : Real] [bottom : Real])
+                         (get-param-vs/set-view->dc! left right top bottom)))])
+          (set! left left-val)
+          (set! right right-val)
+          (set! top top-val)
+          (set! bottom bottom-val))))
 
     ;; When an aspect ratio has been defined, adjust the margins so that the
     ;; actual plot area maintains this ratio.

plot-lib/plot/private/plot3d/plot-area.rkt

@@ -422,7 +422,8 @@
                                      legend
                                      (vector (ivl dc-x-min (+ dc-x-min dc-x-size))
                                              (ivl dc-y-min (+ dc-y-min dc-y-size)))
-                                     (legend-anchor->anchor legend-anchor)))]
+                                     (legend-anchor->anchor legend-anchor)
+                                     (plot-legend-padding)))]
              [none (λ () (values 0 0 title-margin 0))])
         (cond
           [legend-rect
@@ -978,16 +979,23 @@
     (define: right : Real  0)
     (define: top : Real  0)
     (define: bottom : Real  0)
-    (let-values ([(left-val right-val top-val bottom-val)
-                  (margin-fixpoint 0 dc-x-size 0 dc-y-size
-                                   init-left-margin  init-right-margin
-                                   init-top-margin   init-bottom-margin
-                                   (λ ([left : Real] [right : Real] [top : Real] [bottom : Real])
-                                     (get-param-vs/set-view->dc! left right top bottom)))])
-      (set! left left-val)
-      (set! right right-val)
-      (set! top top-val)
-      (set! bottom bottom-val))
+    (let ([inset (plot-inset)])
+      (let-values ([(left-inset right-inset top-inset bottom-inset)
+                    (if (list? inset)
+                        (values (list-ref inset 0) (list-ref inset 1) (list-ref inset 2) (list-ref inset 3))
+                        (values inset inset inset inset))])
+        (let-values ([(left-val right-val top-val bottom-val)
+                      (margin-fixpoint
+                       left-inset        (- dc-x-size right-inset)
+                       top-inset         (- dc-y-size bottom-inset)
+                       init-left-margin  init-right-margin
+                       init-top-margin   init-bottom-margin
+                       (λ ([left : Real] [right : Real] [top : Real] [bottom : Real])
+                         (get-param-vs/set-view->dc! left right top bottom)))])
+          (set! left left-val)
+          (set! right right-val)
+          (set! top top-val)
+          (set! bottom bottom-val))))
 
     ;; When an aspect ratio has been defined, adjust the margins so that the
     ;; actual plot area maintains this ratio.

plot-lib/plot/private/utils-and-no-gui.rkt

@@ -105,7 +105,9 @@
  plot-legend-anchor
  plot-legend-box-alpha
  plot-legend-layout
+ plot-legend-padding
  plot-decorations?
+ plot-inset
  plot-animating?
  plot-pen-color-map
  plot-brush-color-map

plot-test/plot/tests/PRs/124.rkt

@@ -0,0 +1,33 @@
+#lang racket
+
+(require rackunit
+         plot racket/runtime-path
+         "../helpers.rkt")
+
+;; see https://github.com/racket/plot/pull/124
+
+(define-runtime-path pr124-data "./test-data/pr124.dat")
+
+(define (do-plot-pr124 output-fn)
+  (parameterize
+      ([plot-line-width 15]
+       [line-width 15]
+       [plot-inset '(0 10 10 0)]
+       [plot-pen-color-map 'set1]
+       [plot-legend-padding '(0 15 0 0)]
+       [plot-line-cap 'round]
+       [line-cap 'round])
+    (output-fn
+     (list
+      (function sin -5 5 #:color 0 #:label "sin(x)")
+      (function cos -5 5 #:color 1 #:label "cos(x)")))))
+
+(define pr124-test-suite
+  (test-suite
+   "PR#124: Add plot-inset and plot-legend-padding parameters"
+   (test-case "pr124"
+     (check-draw-steps do-plot-pr124 pr124-data))))
+
+(module+ test
+  (require rackunit/text-ui)
+  (run-tests pr124-test-suite))