1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17
18package android.filterfw;
19
20import android.filterfw.core.Filter;
21import android.filterfw.core.FilterFactory;
22import android.filterfw.core.FilterFunction;
23import android.filterfw.core.FrameManager;
24
25/**
26 * A FilterFunctionEnvironment provides a simple functional front-end to manually executing
27 * filters. Use this environment if a graph-based approach is not convenient for your case.
28 * Typically, a FilterFunctionEnvironment is used as follows:
29 *   1. Instantiate a new FilterFunctionEnvironment instance.
30 *   2. Perform any configuration, such as setting a GL environment.
31 *   3. Wrap Filters into FilterFunctions by calling createFunction().
32 *   4. Execute FilterFunctions individually and use the results for further processing.
33 * Additionally, there is a convenience method to execute a number of filters in sequence.
34 * @hide
35 */
36public class FilterFunctionEnvironment extends MffEnvironment {
37
38    /**
39     * Create a new FilterFunctionEnvironment with the default components.
40     */
41    public FilterFunctionEnvironment() {
42        super(null);
43    }
44
45    /**
46     * Create a new FilterFunctionEnvironment with a custom FrameManager. Pass null to auto-create
47     * a FrameManager.
48     *
49     * @param frameManager The FrameManager to use, or null to auto-create one.
50     */
51    public FilterFunctionEnvironment(FrameManager frameManager) {
52        super(frameManager);
53    }
54
55    /**
56     * Create a new FilterFunction from a specific filter class. The function is initialized with
57     * the given key-value list of parameters. Note, that this function uses the default shared
58     * FilterFactory to create the filter instance.
59     *
60     * @param filterClass   The class of the filter to wrap. This must be a Filter subclass.
61     * @param parameters    An argument list of alternating key-value filter parameters.
62     * @return             A new FilterFunction instance.
63     */
64    public FilterFunction createFunction(Class filterClass, Object... parameters) {
65        String filterName = "FilterFunction(" + filterClass.getSimpleName() + ")";
66        Filter filter = FilterFactory.sharedFactory().createFilterByClass(filterClass, filterName);
67        filter.initWithAssignmentList(parameters);
68        return new FilterFunction(getContext(), filter);
69    }
70
71    /**
72     * Convenience method to execute a sequence of filter functions. Note that every function in
73     * the list MUST have one input and one output port, except the first filter (which must not
74     * have any input ports) and the last filter (which may not have any output ports).
75     *
76     * @param functions A list of filter functions. The first filter must be a source filter.
77     * @return         The result of the last filter executed, or null if the last filter did not
78                        produce any output.
79     *
80    public Frame executeSequence(FilterFunction[] functions) {
81        Frame oldFrame = null;
82        Frame newFrame = null;
83        for (FilterFunction filterFunction : functions) {
84            if (oldFrame == null) {
85                newFrame = filterFunction.executeWithArgList();
86            } else {
87                newFrame = filterFunction.executeWithArgList(oldFrame);
88                oldFrame.release();
89            }
90            oldFrame = newFrame;
91        }
92        if (oldFrame != null) {
93            oldFrame.release();
94        }
95        return newFrame;
96    }*/
97
98}
99