Fix final confusion between format and encoding.

Format is file format like jpg, bmp and more,
encoding is color encoding like bgr8, rgb8 and more.

cv_bridge/include/cv_bridge/cv_bridge.h

@@ -277,7 +277,7 @@ struct CvtColorForDisplayOptions {
  * encoding image is passed.
  * - if the output encoding is not empty, it must have sensor_msgs::image_encodings::isColor and
  * isMono return true. It must also be 8 bit in depth
- * - if the input encoding is an OpenCV format (e.g. 8UC1), and if we have 1,3 or 4 channels, it is
+ * - if the input encoding is an OpenCV encoding (e.g. 8UC1), and if we have 1,3 or 4 channels, it is
  * respectively converted to mono, BGR or BGRA.
  * - if the input encoding is 32SC1, this estimate that image as label image and will convert it as
  * bgr image with different colors for each label.

cv_bridge/python/cv_bridge/core.py

@@ -111,7 +111,7 @@ def compressed_imgmsg_to_cv2(self, cmprs_img_msg, desired_encoding = "passthroug
         :rtype: :cpp:type:`cv::Mat`
         :raises CvBridgeError: when conversion is not possible.
 
-        If desired_encoding is ``"passthrough"``, then the returned image has the same format as img_msg.
+        If desired_encoding is ``"passthrough"``, then the returned image has the same encoding as img_msg.
         Otherwise desired_encoding must be one of the standard image encodings
 
         This function returns an OpenCV :cpp:type:`cv::Mat` message on success, or raises :exc:`cv_bridge.CvBridgeError` on failure.
@@ -151,7 +151,7 @@ def imgmsg_to_cv2(self, img_msg, desired_encoding = "passthrough"):
         :rtype: :cpp:type:`cv::Mat`
         :raises CvBridgeError: when conversion is not possible.
 
-        If desired_encoding is ``"passthrough"``, then the returned image has the same format as img_msg.
+        If desired_encoding is ``"passthrough"``, then the returned image has the same encoding as img_msg.
         Otherwise desired_encoding must be one of the standard image encodings
 
         This function returns an OpenCV :cpp:type:`cv::Mat` message on success, or raises :exc:`cv_bridge.CvBridgeError` on failure.

cv_bridge/src/cv_bridge.cpp

@@ -134,16 +134,16 @@ Encoding getEncoding(const std::string& encoding)
   return INVALID;
 }
 
-static const int SAME_FORMAT = -1;
+static const int SAME_ENCODING = -1;
 
-/** Return a lit of OpenCV conversion codes to get from one Format to the other
- * The key is a pair: <FromFormat, ToFormat> and the value a succession of OpenCV code conversion
+/** Return a lit of OpenCV conversion codes to get from one encoding to the other
+ * The key is a pair: <FromEncoding, ToEncoding> and the value a succession of OpenCV code conversion
  * It's not efficient code but it is only called once and the structure is small enough
  */
 std::map<std::pair<Encoding, Encoding>, std::vector<int> > getConversionCodes() {
   std::map<std::pair<Encoding, Encoding>, std::vector<int> > res;
   for(int i=0; i<=5; ++i)
-    res[std::pair<Encoding, Encoding>(Encoding(i),Encoding(i))].push_back(SAME_FORMAT);
+    res[std::pair<Encoding, Encoding>(Encoding(i),Encoding(i))].push_back(SAME_ENCODING);
 
   res[std::make_pair(GRAY, RGB)].push_back(cv::COLOR_GRAY2RGB);
   res[std::make_pair(GRAY, BGR)].push_back(cv::COLOR_GRAY2BGR);
@@ -200,30 +200,30 @@ const std::vector<int> getConversionCode(std::string src_encoding, std::string d
 {
   Encoding src_encod = getEncoding(src_encoding);
   Encoding dst_encod = getEncoding(dst_encoding);
-  bool is_src_color_format = enc::isColor(src_encoding) || enc::isMono(src_encoding) ||
+  bool is_src_color_encoding = enc::isColor(src_encoding) || enc::isMono(src_encoding) ||
                              enc::isBayer(src_encoding) || (src_encoding == enc::YUV422);
-  bool is_dst_color_format = enc::isColor(dst_encoding) || enc::isMono(dst_encoding) ||
+  bool is_dst_color_encoding = enc::isColor(dst_encoding) || enc::isMono(dst_encoding) ||
                              enc::isBayer(dst_encoding) || (dst_encoding == enc::YUV422);
   bool is_num_channels_the_same = (enc::numChannels(src_encoding) == enc::numChannels(dst_encoding));
 
-  // If we have no color info in the source, we can only convert to the same format which
+  // If we have no color info in the source, we can only convert to the same encoding which
   // was resolved in the previous condition. Otherwise, fail
-  if (!is_src_color_format) {
-    if (is_dst_color_format)
-      throw Exception("[" + src_encoding + "] is not a color format. but [" + dst_encoding +
+  if (!is_src_color_encoding) {
+    if (is_dst_color_encoding)
+      throw Exception("[" + src_encoding + "] is not a color encoding. but [" + dst_encoding +
                       "] is. The conversion does not make sense");
     if (!is_num_channels_the_same)
       throw Exception("[" + src_encoding + "] and [" + dst_encoding + "] do not have the same number of channel");
-    return std::vector<int>(1, SAME_FORMAT);
+    return std::vector<int>(1, SAME_ENCODING);
   }
 
   // If we are converting from a color type to a non color type, we can only do so if we stick
   // to the number of channels
-  if (!is_dst_color_format) {
+  if (!is_dst_color_encoding) {
     if (!is_num_channels_the_same)
-      throw Exception("[" + src_encoding + "] is a color format but [" + dst_encoding + "] " +
+      throw Exception("[" + src_encoding + "] is a color encoding but [" + dst_encoding + "] " +
                       "is not so they must have the same OpenCV type, CV_8UC3, CV16UC1 ....");
-    return std::vector<int>(1, SAME_FORMAT);
+    return std::vector<int>(1, SAME_ENCODING);
   }
 
   // If we are converting from a color type to another type, then everything is fine
@@ -238,7 +238,7 @@ const std::vector<int> getConversionCode(std::string src_encoding, std::string d
   // And deal with depth differences if the colors are different
   std::vector<int> res = val->second;
   if ((enc::bitDepth(src_encoding) != enc::bitDepth(dst_encoding)) && (getEncoding(src_encoding) != getEncoding(dst_encoding)))
-    res.push_back(SAME_FORMAT);
+    res.push_back(SAME_ENCODING);
 
   return res;
 }
@@ -320,7 +320,7 @@ CvImagePtr toCvCopyImpl(const cv::Mat& source,
     cv::Mat image2;
     for(size_t i=0; i<conversion_codes.size(); ++i) {
       int conversion_code = conversion_codes[i];
-      if (conversion_code == SAME_FORMAT)
+      if (conversion_code == SAME_ENCODING)
       {
         // Same number of channels, but different bit depth
         int src_depth = enc::bitDepth(src_encoding);
@@ -550,7 +550,7 @@ CvImageConstPtr cvtColorForDisplay(const CvImageConstPtr& source,
   {
     try
     {
-      // Let's decide upon an output format
+      // Let's decide upon an output encoding
       if (enc::numChannels(source->encoding) == 1)
       {
         if ((source->encoding == enc::TYPE_32SC1) ||
@@ -661,13 +661,13 @@ CvImageConstPtr cvtColorForDisplay(const CvImageConstPtr& source,
     return cvtColor(img_scaled, encoding);
   }
 
-  // If no color conversion is possible, we must "guess" the input format
+  // If no color conversion is possible, we must "guess" the input encoding
   CvImagePtr source_typed(new CvImage());
   source_typed->image = source->image;
   source_typed->header = source->header;
   source_typed->encoding = source->encoding;
 
-  // If we get the OpenCV format, if we have 1,3 or 4 channels, we are most likely in mono, BGR or BGRA modes
+  // If we get the OpenCV encoding, if we have 1,3 or 4 channels, we are most likely in mono, BGR or BGRA modes
   if (source->encoding == "CV_8UC1")
     source_typed->encoding = enc::MONO8;
   else if (source->encoding == "16UC1")
@@ -687,7 +687,7 @@ CvImageConstPtr cvtColorForDisplay(const CvImageConstPtr& source,
 
   try
   {
-    // Now that the output is a proper color format, try to see if any conversion is possible
+    // Now that the output is a proper color encoding, try to see if any conversion is possible
     return cvtColor(source_typed, encoding);
   }
   catch (cv_bridge::Exception& e)