From 4612b4b8276eba25f6fba4af20073d930d6c9820 Mon Sep 17 00:00:00 2001
From: Alexander Karsakov <alexander.karsakov@itseez.com>
Date: Tue, 13 May 2014 15:21:47 +0400
Subject: [PATCH] Added clamp() for THRESH_TRUNC mode

---
 modules/imgproc/src/opencl/threshold.cl | 12 ++++++------
 modules/imgproc/src/thresh.cpp          |  6 +++++-
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/modules/imgproc/src/opencl/threshold.cl b/modules/imgproc/src/opencl/threshold.cl
index 5049426a53..6282aa86f8 100644
--- a/modules/imgproc/src/opencl/threshold.cl
+++ b/modules/imgproc/src/opencl/threshold.cl
@@ -53,7 +53,7 @@
 
 __kernel void threshold(__global const uchar * srcptr, int src_step, int src_offset,
                         __global uchar * dstptr, int dst_step, int dst_offset, int rows, int cols,
-                        T1 thresh, T1 max_val)
+                        T1 thresh, T1 max_val, T1 min_val)
 {
     int gx = get_global_id(0);
     int gy = get_global_id(1);
@@ -67,15 +67,15 @@ __kernel void threshold(__global const uchar * srcptr, int src_step, int src_off
         __global T * dst = (__global T *)(dstptr + dst_index);
 
 #ifdef THRESH_BINARY
-        dst[0] = sdata > (T)(thresh) ? (T)(max_val) : (T)(0);
+        dst[0] = sdata > (thresh) ? (T)(max_val) : (T)(0);
 #elif defined THRESH_BINARY_INV
-        dst[0] = sdata > (T)(thresh) ? (T)(0) : (T)(max_val);
+        dst[0] = sdata > (thresh) ? (T)(0) : (T)(max_val);
 #elif defined THRESH_TRUNC
-        dst[0] = sdata > (T)(thresh) ? (T)(thresh) : sdata;
+        dst[0] = clamp(sdata, (T)min_val, (T)(thresh));
 #elif defined THRESH_TOZERO
-        dst[0] = sdata > (T)(thresh) ? sdata : (T)(0);
+        dst[0] = sdata > (thresh) ? sdata : (T)(0);
 #elif defined THRESH_TOZERO_INV
-        dst[0] = sdata > (T)(thresh) ? (T)(0) : sdata;
+        dst[0] = sdata > (thresh) ? (T)(0) : sdata;
 #endif
     }
 }
diff --git a/modules/imgproc/src/thresh.cpp b/modules/imgproc/src/thresh.cpp
index e6a55d700d..b32a4365cf 100644
--- a/modules/imgproc/src/thresh.cpp
+++ b/modules/imgproc/src/thresh.cpp
@@ -847,9 +847,13 @@ static bool ocl_threshold( InputArray _src, OutputArray _dst, double & thresh, d
     if (depth <= CV_32S)
         thresh = cvFloor(thresh);
 
+    const double min_vals[] = { 0, CHAR_MIN, 0, SHRT_MIN, INT_MIN, -FLT_MAX, -DBL_MAX, 0 };
+    double min_val = min_vals[depth];
+
     k.args(ocl::KernelArg::ReadOnlyNoSize(src), ocl::KernelArg::WriteOnly(dst, cn, kercn),
            ocl::KernelArg::Constant(Mat(1, 1, depth, Scalar::all(thresh))),
-           ocl::KernelArg::Constant(Mat(1, 1, depth, Scalar::all(maxval))));
+           ocl::KernelArg::Constant(Mat(1, 1, depth, Scalar::all(maxval))),
+           ocl::KernelArg::Constant(Mat(1, 1, depth, Scalar::all(min_val))));
 
     size_t globalsize[2] = { dst.cols * cn / kercn, dst.rows };
     return k.run(2, globalsize, NULL, false);