Merge pull request #69 from rainyl/issue68

better exception for cv.imencode

Author: rainyl

lib/src/imgcodecs/imgcodecs.dart

@@ -8,6 +8,8 @@ import 'package:ffi/ffi.dart';
 import '../core/base.dart';
 import '../core/mat.dart';
 import '../core/vec.dart';
+import '../core/exception.dart';
+import '../core/error_code.dart';
 import '../constants.g.dart';
 import '../opencv.g.dart' as cvg;
 
@@ -61,17 +63,18 @@ Uint8List imencode(
   InputArray img, {
   VecInt? params,
 }) {
-  return using<Uint8List>((arena) {
-    final buffer = calloc<cvg.VecUChar>();
-    final cExt = ext.toNativeUtf8(allocator: arena);
+  final buffer = calloc<cvg.VecUChar>();
+  final success = calloc<ffi.Bool>();
+  final cExt = ext.toNativeUtf8().cast<ffi.Char>();
 
-    if (params == null) {
-      CFFI.Image_IMEncode(cExt.cast(), img.ref, buffer);
-    } else {
-      CFFI.Image_IMEncode_WithParams(cExt.cast(), img.ref, params.ref, buffer);
-    }
-    return VecUChar.fromPointer(buffer).toU8List();
-  });
+  params == null
+      ? cvRun(() => CFFI.Image_IMEncode(cExt, img.ref, success, buffer))
+      : cvRun(() => CFFI.Image_IMEncode_WithParams(cExt, img.ref, params.ref, success, buffer));
+  if (!success.value) {
+    throw CvException(ErrorCode.StsError.code, msg: "imencode failed, check your params");
+  }
+  calloc.free(cExt);
+  return VecUChar.fromPointer(buffer).toU8List();
 }
 
 /// imdecode reads an image from a buffer in memory.

lib/src/opencv.g.dart

@@ -4892,44 +4892,53 @@ class CvNative {
   CvStatus Image_IMEncode(
     ffi.Pointer<ffi.Char> fileExt,
     Mat img,
+    ffi.Pointer<ffi.Bool> success,
     ffi.Pointer<VecUChar> rval,
   ) {
     return _Image_IMEncode(
       fileExt,
       img,
+      success,
       rval,
     );
   }
 
   late final _Image_IMEncodePtr = _lookup<
       ffi.NativeFunction<
-          CvStatus Function(ffi.Pointer<ffi.Char>, Mat,
+          CvStatus Function(ffi.Pointer<ffi.Char>, Mat, ffi.Pointer<ffi.Bool>,
               ffi.Pointer<VecUChar>)>>('Image_IMEncode');
   late final _Image_IMEncode = _Image_IMEncodePtr.asFunction<
-      CvStatus Function(ffi.Pointer<ffi.Char>, Mat, ffi.Pointer<VecUChar>)>();
+      CvStatus Function(ffi.Pointer<ffi.Char>, Mat, ffi.Pointer<ffi.Bool>,
+          ffi.Pointer<VecUChar>)>();
 
   CvStatus Image_IMEncode_WithParams(
     ffi.Pointer<ffi.Char> fileExt,
     Mat img,
     VecInt params,
+    ffi.Pointer<ffi.Bool> success,
     ffi.Pointer<VecUChar> rval,
   ) {
     return _Image_IMEncode_WithParams(
       fileExt,
       img,
       params,
+      success,
       rval,
     );
   }
 
   late final _Image_IMEncode_WithParamsPtr = _lookup<
       ffi.NativeFunction<
-          CvStatus Function(ffi.Pointer<ffi.Char>, Mat, VecInt,
+          CvStatus Function(
+              ffi.Pointer<ffi.Char>,
+              Mat,
+              VecInt,
+              ffi.Pointer<ffi.Bool>,
               ffi.Pointer<VecUChar>)>>('Image_IMEncode_WithParams');
   late final _Image_IMEncode_WithParams =
       _Image_IMEncode_WithParamsPtr.asFunction<
-          CvStatus Function(
-              ffi.Pointer<ffi.Char>, Mat, VecInt, ffi.Pointer<VecUChar>)>();
+          CvStatus Function(ffi.Pointer<ffi.Char>, Mat, VecInt,
+              ffi.Pointer<ffi.Bool>, ffi.Pointer<VecUChar>)>();
 
   CvStatus Image_IMRead(
     ffi.Pointer<ffi.Char> filename,

lib/src/video/video.dart

@@ -337,11 +337,9 @@ class KalmanFilter extends CvStruct<cvg.KalmanFilter> {
 
   Mat predict({Mat? control}) {
     final p = calloc<cvg.Mat>();
-    if (control == null) {
-      cvRun(() => CFFI.KalmanFilter_Predict(ref, p));
-    } else {
-      CFFI.KalmanFilter_PredictWithParams(ref, control.ref, p);
-    }
+    control == null
+        ? cvRun(() => CFFI.KalmanFilter_Predict(ref, p))
+        : cvRun(() => CFFI.KalmanFilter_PredictWithParams(ref, control.ref, p));
     return Mat.fromPointer(p);
   }
 

src/imgcodecs/imgcodecs.cpp

@@ -27,19 +27,19 @@ CvStatus Image_IMWrite_WithParams(const char *filename, Mat img, VecInt params,
   *rval = cv::imwrite(filename, *img.ptr, *params.ptr);
   END_WRAP
 }
-CvStatus Image_IMEncode(const char *fileExt, Mat img, VecUChar *rval)
+CvStatus Image_IMEncode(const char *fileExt, Mat img, bool *success, VecUChar *rval)
 {
   BEGIN_WRAP
   auto buf = new std::vector<uchar>();
-  cv::imencode(fileExt, *img.ptr, *buf);
+  *success = cv::imencode(fileExt, *img.ptr, *buf);
   *rval = {buf};
   END_WRAP
 }
-CvStatus Image_IMEncode_WithParams(const char *fileExt, Mat img, VecInt params, VecUChar *rval)
+CvStatus Image_IMEncode_WithParams(const char *fileExt, Mat img, VecInt params, bool *success, VecUChar *rval)
 {
   BEGIN_WRAP
   auto buf = new std::vector<uchar>();
-  cv::imencode(fileExt, *img.ptr, *buf, *params.ptr);
+  *success = cv::imencode(fileExt, *img.ptr, *buf, *params.ptr);
   *rval = {buf};
   END_WRAP
 }

src/imgcodecs/imgcodecs.h

@@ -21,8 +21,9 @@ extern "C" {
 CvStatus Image_IMRead(const char *filename, int flags, CVD_OUT Mat *rval);
 CvStatus Image_IMWrite(const char *filename, Mat img, CVD_OUT bool *rval);
 CvStatus Image_IMWrite_WithParams(const char *filename, Mat img, VecInt params, CVD_OUT bool *rval);
-CvStatus Image_IMEncode(const char *fileExt, Mat img, CVD_OUT VecUChar *rval);
-CvStatus Image_IMEncode_WithParams(const char *fileExt, Mat img, VecInt params, CVD_OUT VecUChar *rval);
+CvStatus Image_IMEncode(const char *fileExt, Mat img, CVD_OUT bool *success, CVD_OUT VecUChar *rval);
+CvStatus Image_IMEncode_WithParams(const char *fileExt, Mat img, VecInt params, CVD_OUT bool *success,
+                                   CVD_OUT VecUChar *rval);
 CvStatus Image_IMDecode(VecUChar buf, int flags, CVD_OUT Mat *rval);
 
 #ifdef __cplusplus