Generalize GR tick label rotations (#3782)

* gr tick rotations

* consistency

* start of angle offset work

* Working!

* simplify logic

* gr tick rotations

* consistency

* start of angle offset work

* Working!

* simplify logic

* all offsets

* Rebase

* tick factor reversion

* Fix for 3d plots

* simplification

* offset update

* bump offset

* Remove conflict error

* Resolve merge conflict error.

* Resolve merge conflict error

* 3d done

* remove excess

* adjust offset

* restore offset

* fix sign check

Co-authored-by: t-bltg <tf.bltg@gmail.com>
Co-authored-by: Simon Christ <SimonChrist@gmx.de>

src/backends/gr.jl

@@ -671,31 +671,19 @@ end
 
 function gr_set_tickfont(sp, letter)
     axis = sp[get_attr_symbol(letter, :axis)]
-
-    # invalidate alignment changes for small rotations (|θ| < 45°)
-    trigger(rot) = abs(sind(rot)) < abs(cosd(rot)) ? 0 : sign(rot)
-
-    rot = axis[:rotation]
-    if letter === :x || (RecipesPipeline.is3d(sp) && letter === :y)
-        halign = (:left, :hcenter, :right)[trigger(rot) + 2]
-        valign = (axis[:mirror] ? :bottom : :top, :vcenter)[trigger(abs(rot)) + 1]
-    else
-        halign = (axis[:mirror] ? :left : :right, :hcenter)[trigger(abs(rot)) + 1]
-        valign = (:top, :vcenter, :bottom)[trigger(rot) + 2]
-    end
     gr_set_font(
         tickfont(axis),
         sp,
-        halign = halign,
-        valign = valign,
         rotation = axis[:rotation],
         color = axis[:tickfontcolor],
     )
 end
 
+# size of the text with no rotation
 function gr_text_size(str)
     GR.savestate()
     GR.selntran(0)
+    GR.setcharup(0, 1)
     xs, ys = gr_inqtext(0, 0, string(str))
     l, r = extrema(xs)
     b, t = extrema(ys)
@@ -705,9 +693,11 @@ function gr_text_size(str)
     return w, h
 end
 
+# size of the text with rotation applied
 function gr_text_size(str, rot)
     GR.savestate()
     GR.selntran(0)
+    GR.setcharup(0, 1)
     xs, ys = gr_inqtext(0, 0, string(str))
     l, r = extrema(xs)
     b, t = extrema(ys)
@@ -720,6 +710,15 @@ end
 text_box_width(w, h, rot) = abs(cosd(rot)) * w + abs(cosd(rot + 90)) * h
 text_box_height(w, h, rot) = abs(sind(rot)) * w + abs(sind(rot + 90)) * h
 
+function gr_get_3d_axis_angle(cvs, nt, ft, letter)
+    length(cvs) < 2 && return 0
+    tickpoints = [gr_w3tondc(sort_3d_axes(cv, nt, ft, letter)...) for cv ∈ cvs]
+
+    dx = tickpoints[2][1] - tickpoints[1][1]
+    dy = tickpoints[2][2] - tickpoints[1][2]
+    return atand(dy, dx)
+end
+
 function gr_get_ticks_size(ticks, rot)
     w, h = 0.0, 0.0
     for (cv, dv) in zip(ticks...)
@@ -1560,13 +1559,35 @@ function gr_label_ticks(sp, letter, ticks)
     oamin, oamax = axis_limits(sp, oletter)
     gr_set_tickfont(sp, letter)
     out_factor = ifelse(axis[:tick_direction] === :out, 1.5, 1)
-    x_offset = isy ? -1.5e-2 * out_factor : 0
+    x_base_offset = isy ? -1.5e-2 * out_factor : 0
-    y_offset = isy ? 0 : -8e-3 * out_factor
+    y_base_offset = isy ? 0 : -8e-3 * out_factor
     
+    rot = axis[:rotation] % 360
     ov = sp[:framestyle] == :origin ? 0 : xor(oaxis[:flip], axis[:mirror]) ? oamax : oamin
     sgn = axis[:mirror] ? -1 : 1
+    sgn2 = iseven(Int(floor(rot / 90))) ? -1 : 1
+    sgn3 = if isy
+                -360 < rot < -180 || 0 < rot < 180 ? 1 : -1
+            else
+                rot < -270 || -90 < rot < 90 || rot > 270 ? 1 : -1
+            end
     for (cv, dv) in zip(ticks...)
         x, y = GR.wctondc(reverse_if((cv, ov), isy)...)
+        sz_rot = gr_text_size(dv, rot)
+        sz = gr_text_size(dv)
+        x_offset = x_base_offset
+        y_offset = y_base_offset
+        if isy
+            x_offset += -first(sz_rot) / 2
+            if rot % 90 != 0
+                y_offset += sgn2 * last(sz_rot) / 2 + sgn3 * last(sz) * cosd(rot) / 2
+            end
+        else
+            if rot % 90 != 0
+                x_offset += sgn2 * first(sz_rot) / 2 + sgn3 * last(sz) * sind(rot) / 2
+            end
+            y_offset += -last(sz_rot) / 2
+        end
         gr_text(x + sgn * x_offset, y + sgn * y_offset, dv)
     end
 end
@@ -1577,6 +1598,9 @@ function gr_label_ticks_3d(sp, letter, ticks)
     near_letter = letter in (:x, :z) ? :y : :x
     far_letter = letter in (:x, :y) ? :z : :x
 
+    isy = letter === :y
+    isz = letter === :z
+
     ax = sp[get_attr_symbol(letter, :axis)]
     nax = sp[get_attr_symbol(near_letter, :axis)]
     fax = sp[get_attr_symbol(far_letter, :axis)]
@@ -1584,7 +1608,7 @@ function gr_label_ticks_3d(sp, letter, ticks)
     amin, amax = axis_limits(sp, letter)
     namin, namax = axis_limits(sp, near_letter)
     famin, famax = axis_limits(sp, far_letter)
-    n0, n1 = letter === :y ? (namax, namin) : (namin, namax)
+    n0, n1 = isy ? (namax, namin) : (namin, namax)
 
     # find out which axes we are dealing with
     i = findfirst(==(letter), (:x, :y, :z))
@@ -1601,27 +1625,52 @@ function gr_label_ticks_3d(sp, letter, ticks)
     nt = sp[:framestyle] == :origin ? 0 : ax[:mirror] ? n1 : n0
     ft = sp[:framestyle] == :origin ? 0 : ax[:mirror] ? famax : famin
 
-    xoffset = if letter === :x
+    rot = mod(ax[:rotation], 360)
-        (sp[:yaxis][:mirror] ? 1 : -1) * 1e-2 * (sp[:xaxis][:tick_direction] == :out ? 1.5 : 1)
+    sgn = ax[:mirror] ? -1 : 1
-    elseif letter === :y
-        (sp[:yaxis][:mirror] ? -1 : 1) * 1e-2 * (sp[:yaxis][:tick_direction] == :out ? 1.5 : 1)
-    else
-        (sp[:zaxis][:mirror] ? 1 : -1) * 1e-2 * (sp[:zaxis][:tick_direction] == :out ? 1.5 : 1)
-    end
-    yoffset = if letter === :x
-        (sp[:xaxis][:mirror] ? 1 : -1) * 1e-2 * (sp[:xaxis][:tick_direction] == :out ? 1.5 : 1)
-    elseif letter === :y
-        (sp[:yaxis][:mirror] ? 1 : -1) * 1e-2 * (sp[:yaxis][:tick_direction] == :out ? 1.5 : 1)
-    else
-        0
-    end
 
     cvs, dvs = ticks
     ax[:flip] && reverse!(cvs)
 
+    axisθ = isz ? 270 : mod(gr_get_3d_axis_angle(cvs, nt, ft, letter), 360) # issue: doesn't work with 1 tick
+    axisϕ = mod(axisθ - 90, 360)
+
+    out_factor = ifelse(ax[:tick_direction] === :out, 1.5, 1)
+    axisoffset = out_factor * 1.2e-2
+    x_base_offset = axisoffset * cosd(axisϕ)
+    y_base_offset = axisoffset * sind(axisϕ)
+
+    sgn2a = sgn2b = sgn3 = 0
+    if axisθ != 0 || rot % 90 != 0
+        sgn2a = (axisθ != 90) &&
+        (axisθ == 0 && (rot < 90 || 180 ≤ rot < 270)) ||
+        (axisθ == 270) ||
+        (axisθ < 90 && (axisθ < rot < 90 || axisθ + 180 < rot < 270)) ||
+        (axisθ > 270 && (rot < 90 || axisθ - 180 < rot < 270 || rot > axisθ)) ? -1 : 1
+    end
+
+    if (axisθ - 90) % 180 != 0 || (rot - 90) % 180 != 0
+        sgn2b = axisθ == 0 ||
+        (axisθ == 90 && (90 ≤ rot < 180 || 270 ≤ rot < 360)) ||
+        (axisθ == 270 && (rot < 90 || 180 ≤ rot < 270)) ||
+        (axisθ < 90 && (axisθ < rot < 180 || axisθ + 180 < rot)) ||
+        (axisθ > 270 && (rot < axisθ - 180 || 180 ≤ rot < axisθ)) ? -1 : 1
+    end
+
+    if !(axisθ == 0 && rot % 180 == 0) && ((rot - 90) % 180 != 0)
+        sgn3 = (axisθ == 0 && 90 < rot < 270) ||
+        (axisθ == 90 && rot < 180) ||
+        (axisθ == 270 && rot > 180) ||
+        (axisθ < 90 && (rot < axisθ || 90 ≤ rot < 180 || axisθ + 180 < rot < 270)) ||
+        (axisθ > 270 && (90 ≤ rot < axisθ - 180 || 180 ≤ rot < 270 || rot > axisθ)) ? -1 : 1
+    end
+
     for (cv, dv) in zip((cvs, dvs)...)
         xi, yi = gr_w3tondc(sort_3d_axes(cv, nt, ft, letter)...)
-        gr_text(xi + xoffset, yi + yoffset, dv)
+        sz_rot = gr_text_size(dv, rot)
+        sz = gr_text_size(dv)
+        x_offset = x_base_offset + sgn2a * first(sz_rot) / 2 + sgn3 * last(sz) * sind(rot) / 2
+        y_offset = y_base_offset + sgn2b * last(sz_rot) / 2 + sgn3 * last(sz) * cosd(rot) / 2
+        gr_text(xi + sgn * x_offset, yi + sgn * y_offset, dv)
     end
 end
 
@@ -2084,3 +2133,4 @@ function _display(plt::Plot{GRBackend})
 end
 
 closeall(::GRBackend) = GR.emergencyclosegks()
+