diff --git a/src/framebuffer2.h b/src/framebuffer2.h
--- a/src/framebuffer2.h
+++ b/src/framebuffer2.h
@@ -25,7 +25,7 @@
 
 struct Range
 {
-    double min, max;
+    double start, end;
 };
 
 /// Abstract base class for all frame buffers.
diff --git a/src/indexbuffer.h b/src/indexbuffer.h
--- a/src/indexbuffer.h
+++ b/src/indexbuffer.h
@@ -24,7 +24,9 @@
 #include "framebuffer2.h"
 
 /// A simple frame buffer that simply returns requested index as
-/// value.
+/// sample value.
+///
+/// @note This buffer isn't for storing data.
 class IndexBuffer : public ResizableBuffer
 {
 public:
diff --git a/src/linindexbuffer.cpp b/src/linindexbuffer.cpp
new file mode 100644
--- /dev/null
+++ b/src/linindexbuffer.cpp
@@ -0,0 +1,57 @@
+ /*
+  Copyright © 2017 Hasan Yavuz Özderya
+
+  This file is part of serialplot.
+
+  serialplot is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  serialplot is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with serialplot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <QtGlobal>
+
+#include "linindexbuffer.h"
+
+LinIndexBuffer::LinIndexBuffer(unsigned n, Range lim)
+{
+    Q_ASSERT(n > 0);
+
+    _size = n;
+    setLimits(lim);
+}
+
+unsigned LinIndexBuffer::size() const
+{
+    return _size;
+}
+
+double LinIndexBuffer::sample(unsigned i) const
+{
+    return _limits.start + i * _step;
+}
+
+Range LinIndexBuffer::limits() const
+{
+    return _limits;
+}
+
+void LinIndexBuffer::resize(unsigned n)
+{
+    _size = n;
+    setLimits(_limits);         // called to update `_step`
+}
+
+void LinIndexBuffer::setLimits(Range lim)
+{
+    _limits = lim;
+    _step = (lim.end - lim.start) / (_size-1);
+}
diff --git a/src/linindexbuffer.h b/src/linindexbuffer.h
new file mode 100644
--- /dev/null
+++ b/src/linindexbuffer.h
@@ -0,0 +1,50 @@
+ /*
+  Copyright © 2017 Hasan Yavuz Özderya
+
+  This file is part of serialplot.
+
+  serialplot is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  serialplot is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with serialplot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef LININDEXBUFFER_H
+#define LININDEXBUFFER_H
+
+// IMPORTANT TODO: rename to "framebuffer.h" when stream work is done.
+#include "framebuffer2.h"
+
+/// A dynamic frame buffer that start and end values can be set and
+/// intermediate values are calculated linearly.
+///
+/// @note This buffer isn't for storing data.
+class LinIndexBuffer : public ResizableBuffer
+{
+public:
+    LinIndexBuffer(unsigned n, Range lim);
+    LinIndexBuffer(unsigned n, double min, double max) :
+        LinIndexBuffer(n, {min, max}) {};
+
+    unsigned size() const;
+    double sample(unsigned i) const;
+    Range limits() const;
+    void resize(unsigned n);
+    /// Sets minimum and maximum sample values of the buffer.
+    void setLimits(Range lim);
+
+private:
+    unsigned _size;
+    Range _limits;
+    double _step;
+};
+
+#endif
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -28,6 +28,7 @@ add_executable(Test EXCLUDE_FROM_ALL
   ../src/sink.cpp
   ../src/source.cpp
   ../src/indexbuffer.cpp
+  ../src/linindexbuffer.cpp
   )
 add_test(NAME test1 COMMAND Test)
 qt5_use_modules(Test Widgets)
diff --git a/tests/test.cpp b/tests/test.cpp
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -23,6 +23,7 @@
 #include "samplepack.h"
 #include "source.h"
 #include "indexbuffer.h"
+#include "linindexbuffer.h"
 
 TEST_CASE("samplepack with no X", "[memory]")
 {
@@ -192,13 +193,46 @@ TEST_CASE("IndexBuffer", "[memory, buffe
         REQUIRE(buf.sample(i) == i);
     }
     auto l = buf.limits();
-    REQUIRE(l.min == 0);
-    REQUIRE(l.max == 9);
+    REQUIRE(l.start == 0);
+    REQUIRE(l.end == 9);
 
     buf.resize(20);
     REQUIRE(buf.size() == 20);
     REQUIRE(buf.sample(15) == 15);
     l = buf.limits();
-    REQUIRE(l.min == 0);
-    REQUIRE(l.max == 19);
+    REQUIRE(l.start == 0);
+    REQUIRE(l.end == 19);
 }
+
+TEST_CASE("LinIndexBuffer", "[memory, buffer]")
+{
+    LinIndexBuffer buf(10, 0., 3.0);
+
+    REQUIRE(buf.size() == 10);
+    REQUIRE(buf.sample(0) == 0.);
+    REQUIRE(buf.sample(9) == 3.0);
+    REQUIRE(buf.sample(4) == Approx(1+1/3.));
+
+    auto l = buf.limits();
+    REQUIRE(l.start == 0.);
+    REQUIRE(l.end == 3.);
+
+    buf.resize(20);
+    REQUIRE(buf.size() == 20);
+    REQUIRE(buf.sample(0) == 0.);
+    REQUIRE(buf.sample(9) == Approx(9.*3./19.));
+    REQUIRE(buf.sample(4) == Approx(4.*3./19.));
+    REQUIRE(buf.sample(19) == 3.0);
+
+    l = buf.limits();
+    REQUIRE(l.start == 0.);
+    REQUIRE(l.end == 3.0);
+
+    buf.setLimits({-5., 5.});
+    l = buf.limits();
+    REQUIRE(l.start == -5.0);
+    REQUIRE(l.end == 5.0);
+
+    REQUIRE(buf.sample(0) == -5.0);
+    REQUIRE(buf.sample(19) == 5.0);
+}