Add nominal documentation for “ops” functions.

docs/index.rst

@@ -12,4 +12,5 @@ Documentation
    distance
    color
    generate
+   ops
    importexport

docs/ops.rst

@@ -0,0 +1,24 @@
+Image Operations
+################
+
+All functions with the ``heman_ops_`` prefix are meant for doing very simple image operations that are outside of heman's core functionality.
+
+.. code-block:: c
+
+    // Given a set of same-sized images, copy them into a horizontal filmstrip.
+    heman_image* heman_ops_stitch_horizontal(heman_image** images, int count);
+
+    // Given a set of same-sized images, copy them into a vertical filmstrip.
+    heman_image* heman_ops_stitch_vertical(heman_image** images, int count);
+
+    // Transform texel values so that [minval, maxval] map to [0, 1] and return the
+    // result.  Values outside the range are clamped.  The source image is
+    // untouched.
+    heman_image* heman_ops_normalize_f32(
+        heman_image* source, HEMAN_FLOAT minval, HEMAN_FLOAT maxval);
+
+    // Generate a monochrome image by applying a step function.
+    heman_image* heman_ops_step(heman_image* image, HEMAN_FLOAT threshold);
+
+    // Generate a height x 1 x 1 image by averaging the values across each row.
+    heman_image* heman_ops_sweep(heman_image* image);