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craiglabenzPiinks
craiglabenz
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Piinks
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Adds mediapipe_vision package (#13)
* adds mediapipe_core package * adds makefile for all packages * fixes typo in Makefile * Apply suggestions from code review * Update Makefile * Apply suggestions from code review * updated generated code's location and license (for 3P status) * code review responses including: * comments * licensing * resolving testing nits * updated README * setup sharing of base analysis_options * flutter create * initial commit of vision task * Updates structure of mediapipe_vision package --------- Co-authored-by: Kate Lovett <[email protected]>
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‎packages/mediapipe-core/lib/generated/core_symbols.yaml

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format_version: 1.0.0
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files:
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package:mediapipe_core/src/io/third_party/mediapipe/generated/mediapipe_common_bindings.dart:
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used-config:
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? package:mediapipe_core/src/io/third_party/mediapipe/generated/mediapipe_common_bindings.dart
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: used-config:
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ffi-native: false
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symbols:
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c:@S@BaseOptions:

‎packages/mediapipe-core/lib/src/containers.dart

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// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'dart:ffi';
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import 'package:ffi/ffi.dart';
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import 'package:mediapipe_core/mediapipe_core.dart';
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import 'third_party/mediapipe/generated/mediapipe_common_bindings.dart'
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as bindings;
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/// Dart representation of MediaPipe's "Category" concept.
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///
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/// Category is a util class, that contains a category name, its display name,
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/// a float value as score, and the index of the label in the corresponding
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/// label file. Typically it's used as result of classification or detection
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/// tasks.
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///
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/// See more:
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/// * [MediaPipe's Category documentation](https://developers.google.com/mediapipe/api/solutions/java/com/google/mediapipe/tasks/components/containers/Category)
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class Category {
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/// Generative constructor that creates a [Category] instance.
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const Category({
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required this.index,
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required this.score,
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required this.categoryName,
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required this.displayName,
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});
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/// The index of the label in the corresponding label file.
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final int index;
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/// The probability score of this label category.
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final double score;
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/// The label of this category object.
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final String? categoryName;
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/// The display name of the label, which may be translated for different locales.
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final String? displayName;
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/// Accepts a pointer to a list of structs, and a count representing the length
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/// of the list, and returns a list of pure-Dart [Category] instances.
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static List<Category> fromStructs(
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Pointer<bindings.Category> structs,
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int count,
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) {
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final categories = <Category>[];
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for (int i = 0; i < count; i++) {
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categories.add(fromStruct(structs[i]));
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}
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return categories;
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}
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/// Accepts a pointer to a single struct and returns a pure-Dart [Category] instance.
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static Category fromStruct(bindings.Category struct) {
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return Category(
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index: struct.index,
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score: struct.score,
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categoryName: toDartString(struct.category_name),
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displayName: toDartString(struct.display_name),
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);
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}
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/// Releases all C memory associated with a list of [bindings.Category] pointers.
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/// This method is important to call after calling [Category.fromStructs] to
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/// convert that C memory into pure-Dart objects.
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static void freeStructs(Pointer<bindings.Category> structs, int count) {
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int index = 0;
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while (index < count) {
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bindings.Category obj = structs[index];
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calloc.free(obj.category_name);
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calloc.free(obj.display_name);
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index++;
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}
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calloc.free(structs);
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}
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@override
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String toString() => 'Category(index=$index, score=$score, '
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'categoryName=$categoryName, displayName=$displayName)';
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}
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/// Dart representation of MediaPipe's "Classifications" concept.
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///
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/// Represents the list of classification for a given classifier head.
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/// Typically used as a result for classification tasks.
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///
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/// See also:
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/// * [MediaPipe's Classifications documentation](https://developers.google.com/mediapipe/api/solutions/java/com/google/mediapipe/tasks/components/containers/Classifications)
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class Classifications {
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/// Generative constructor that creates a [Classifications] instance.
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const Classifications({
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required this.categories,
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required this.headIndex,
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required this.headName,
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});
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/// A list of Category objects which contain the actual classification
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/// information, including human-readable labels and probability scores.
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final List<Category> categories;
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/// The index of the classifier head these entries refer to.
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final int headIndex;
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/// The optional name of the classifier head, which is the corresponding
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/// tensor metadata name.
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final String? headName;
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/// Accepts a pointer to a list of structs, and a count representing the length
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/// of the list, and returns a list of pure-Dart [Classifications] instances.
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static List<Classifications> fromStructs(
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Pointer<bindings.Classifications> structs,
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int count,
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) {
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final classifications = <Classifications>[];
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for (int i = 0; i < count; i++) {
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classifications.add(fromStruct(structs[i]));
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}
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return classifications;
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}
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/// Accepts a pointer to a single struct and returns a pure-Dart [Classifications]
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/// instance.
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static Classifications fromStruct(bindings.Classifications struct) {
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return Classifications(
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categories: Category.fromStructs(
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struct.categories,
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struct.categories_count,
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),
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headIndex: struct.head_index,
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headName: toDartString(struct.head_name),
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);
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}
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/// Releases all C memory associated with a list of [bindings.Classifications]
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/// pointers. This method is important to call after calling [Classifications.fromStructs]
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/// to convert that C memory into pure-Dart objects.
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static void freeStructs(
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Pointer<bindings.Classifications> structs,
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int count,
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) {
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int index = 0;
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while (index < count) {
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bindings.Classifications obj = structs[index];
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Category.freeStructs(obj.categories, obj.categories_count);
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calloc.free(obj.head_name);
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index++;
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}
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calloc.free(structs);
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}
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/// Convenience getter for the first [Category] out of the [categories] list.
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Category? get firstCategory =>
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categories.isNotEmpty ? categories.first : null;
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@override
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String toString() {
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final categoryStrings = categories.map((cat) => cat.toString()).join(', ');
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return 'Classification(categories=[$categoryStrings], '
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'headIndex=$headIndex, headName=$headName)';
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}
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}

‎packages/mediapipe-core/lib/src/ffi_utils.dart

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// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'dart:ffi';
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import 'dart:typed_data';
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import 'package:ffi/ffi.dart';
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/// Converts a list of Dart strings into their C memory equivalent.
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///
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/// See also:
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/// * [prepareString]
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Pointer<Pointer<Char>> prepareListOfStrings(List<String> values) {
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final ptrArray = calloc<Pointer<Char>>(values.length);
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for (var i = 0; i < values.length; i++) {
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ptrArray[i] = prepareString(values[i]);
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}
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return ptrArray;
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}
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/// Converts a single Dart string into its C memory equivalent.
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///
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/// See also:
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/// * [prepareListOfStrings]
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Pointer<Char> prepareString(String val) => val.toNativeUtf8().cast<Char>();
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/// Converts the C memory representation of a string into a Dart [String]. If the
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/// supplied pointer is a null pointer, this function returns `null`.
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///
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/// See also:
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/// * [toDartStrings]
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String? toDartString(Pointer<Char> val) {
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if (val.address == 0) return null;
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return val.cast<Utf8>().toDartString();
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}
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/// Converts a list of C memory representations of strings into a list of Dart
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/// [String]s.
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///
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/// See also:
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/// * [toDartString]
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List<String?> toDartStrings(Pointer<Pointer<Char>> val, [int? length]) =>
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length != null
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? _toDartStringsWithCount(val, length)
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: _toStartStringsUntilNull(val);
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List<String?> _toStartStringsUntilNull(Pointer<Pointer<Char>> val) {
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final dartStrings = <String?>[];
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int counter = 0;
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while (true) {
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if (val[counter].address == 0) break;
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dartStrings.add(toDartString(val[counter]));
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counter++;
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}
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return dartStrings;
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}
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List<String?> _toDartStringsWithCount(Pointer<Pointer<Char>> val, int length) {
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final dartStrings = <String?>[];
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int counter = 0;
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while (counter < length) {
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dartStrings.add(toDartString(val[counter]));
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counter++;
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}
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return dartStrings;
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}
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/// Converts Dart's representation for binary data, a [Uint8List], into its C
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/// memory representation.
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Pointer<Char> prepareUint8List(Uint8List ints) {
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final Pointer<Uint8> ptr = calloc<Uint8>(ints.length);
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ptr.asTypedList(ints.length).setAll(0, ints);
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return ptr.cast();
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}
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/// Converts a pointer to binary data in C memory to Dart's representation for
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/// binary data, a [Uint8List].
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Uint8List toUint8List(Pointer<Char> val, {int? length}) {
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final codeUnits = val.cast<Uint8>();
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if (length != null) {
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RangeError.checkNotNegative(length, 'length');
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} else {
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length = _length(codeUnits);
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}
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return codeUnits.asTypedList(length);
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}
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// Counts the non-null bytes in a string to determine its length
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int _length(Pointer<Uint8> codeUnits) {
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var length = 0;
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while (codeUnits[length] != 0) {
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length++;
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}
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return length;
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}

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