better linking

src/recipes.jl

@@ -909,15 +909,37 @@ end
     bbx1 = xl1 + left(inset_bbox).value * (xl2 - xl1)
     bbx2 = bbx1 + width(inset_bbox).value * (xl2 - xl1)
     yl1, yl2 = ylims(plt.subplots[sp_index])
-    bby1 = yl1 + bottom(inset_bbox).value * (yl2 - yl1)
+    bby1 = yl1 + (1 - bottom(inset_bbox).value) * (yl2 - yl1)
     bby2 = bby1 + height(inset_bbox).value * (yl2 - yl1)
     bbx = bbx1 + width(inset_bbox).value * (xl2 - xl1) / 2
+    bby = bby1 + height(inset_bbox).value * (yl2 - yl1) / 2
     lens_index = last(plt.subplots)[:subplot_index] + 1
-    @show plotattributes[:plot_object].subplots
-    @show inset_bbox
-    @show sp[:left_margin]
     x1, x2 = plotattributes[:x]
     y1, y2 = plotattributes[:y]
+    seriestype := :path
+    label := ""
+    linecolor := :lightgray
+    bbx_mag = (x1 + x2) / 2
+    bby_mag = (y1 + y2) / 2
+    xi_lens, yi_lens = intersection_point(bbx_mag, bby_mag, bbx, bby, abs(bby2 - bby1), abs(bbx2 - bbx1))
+    xi_mag, yi_mag = intersection_point(bbx, bby, bbx_mag, bby_mag, abs(y2 - y1), abs(x2 - x1))
+    # add lines
+    if xl1 < xi_lens < xl2 &&
+        yl1 < yi_lens < yl2
+        @series begin
+            subplot := sp_index
+            x := [xi_mag, xi_lens]
+            y := [yi_mag, yi_lens]
+            ()
+        end
+    end
+    # add magnification shape
+    @series begin
+        subplot := sp_index
+        x := [x1, x1, x2, x2, x1]
+        y := [y1, y2, y2, y1, y1]
+        ()
+    end
     # add subplot
     for series in sp.series_list
         @series begin
@@ -929,26 +951,34 @@ end
             ()
         end
     end
-    # TODO: compute better linking
-    seriestype := :path
-    label := ""
-    linecolor := :lightgray
-    # add lines
-    if xl1 < bbx < xl2 &&
-        yl1 < bby1 < yl2
-        @series begin
-            subplot := sp_index
-            x := [(x1 + x2) / 2, bbx]
-            y := [y2, bby1]
-            ()
+end
+
+function intersection_point(xA, yA, xB, yB, h, w)
+    s = (yA - yB) / (xA - xB)
+    @show s, xA, yA, xB, yB, h, w
+    hh = h / 2
+    hw = w / 2
+    # left or right?
+    if -hh <= s * hw <= hh
+        if xA > xB
+            # right
+            println("right")
+            return xB + hw, yB + s * hw
+        else # left
+            println("left")
+            return xB - hw, yB - s * hw
         end
+    # top or bot?
+    elseif -hw <= hh/s <= hw
+        if yA > yB
+            # top
+            println("top")
+            return xB + hh/s, yB + hh
+        else
+            # bottom
+            println("bottom")
+            return xB - hh/s, yB - hh
         end
-    # add magnification shape
-    @series begin
-        subplot := sp_index
-        x := [x1, x1, x2, x2, x1]
-        y := [y1, y2, y2, y1, y1]
-        ()
     end
 end
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