diff --git a/charts-tests.factor b/charts-tests.factor
new file mode 100644
index 0000000000..49bcdaa199
--- /dev/null
+++ b/charts-tests.factor
@@ -0,0 +1,22 @@
+! Copyright (C) 2017 Alexander Ilin.
+
+USING: tools.test charts ;
+IN: charts.tests
+
+! Adjustment after search is required in both directions.
+{
+    {
+        { 1 3 } { 1 4 } { 1 5 }
+        { 2 6 } { 3 7 } { 4 8 }
+        { 5 9 } { 5 10 } { 5 11 } { 5 12 }
+    }
+} [
+    { 1 5 }
+    {
+        { 0 1 } { 0 2 }
+        { 1 3 } { 1 4 } { 1 5 }
+        { 2 6 } { 3 7 } { 4 8 }
+        { 5 9 } { 5 10 } { 5 11 } { 5 12 }
+        { 6 13 } { 7 14 }
+    } clip-data
+] unit-test
diff --git a/charts.factor b/charts.factor
index 8b779f99f7..e8fc499c6b 100644
--- a/charts.factor
+++ b/charts.factor
@@ -1,8 +1,9 @@
 ! Copyright (C) 2016-2017 Alexander Ilin.
 
-USING: accessors colors.constants kernel math opengl opengl.gl
-sequences specialized-arrays.instances.alien.c-types.float
-ui.gadgets ui.render ;
+USING: accessors binary-search colors.constants kernel locals
+math math.order opengl opengl.gl sequences
+specialized-arrays.instances.alien.c-types.float ui.gadgets
+ui.render ;
 IN: charts
 
 TUPLE: chart < gadget ;
@@ -21,6 +22,35 @@ M: chart pref-dim* drop { 300 300 } ;
     [ (line-vertices) gl-vertex-pointer GL_LINES 0 ] keep
     length glDrawArrays ;
 
+<PRIVATE
+
+: search-index ( elt seq -- index elt )
+    [ first <=> ] with search ;
+
+: finder ( elt seq -- seq quot )
+    [ first ] dip [ first = not ] with ; inline
+
+: adjusted-tail ( index elt seq -- seq' )
+    [ finder find-last-from drop ] keep swap [ 1 + tail ] when* ;
+
+: adjusted-head ( index elt seq -- seq' )
+    [ finder find-from drop ] keep swap [ head ] when* ;
+
+:: in-bounds? ( bounds data -- ? )
+    bounds first data last first < not
+    bounds second data first first > not
+    and ;
+
+PRIVATE>
+
+: clip-data ( bounds data -- data' )
+    2dup in-bounds? [
+        [ dup first ] dip [ search-index ] keep adjusted-tail
+        [ second ] dip [ search-index ] keep adjusted-head
+    ] [
+        2drop { } clone
+    ] if ;
+
 ! Return the bottom-left and top-right corners of the visible area.
 : chart-axes ( chart -- seq )
     drop { { 0 300 } { 300 0 } } ;