160 lines
6.5 KiB
C++
160 lines
6.5 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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By using JUCE, you agree to the terms of both the JUCE 5 End-User License
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Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
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27th April 2017).
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End User License Agreement: www.juce.com/juce-5-licence
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Privacy Policy: www.juce.com/juce-5-privacy-policy
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Or: You may also use this code under the terms of the GPL v3 (see
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www.gnu.org/licenses).
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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class AudioThumbnailCache;
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//==============================================================================
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/**
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Provides a base for classes that can store and draw scaled views of an
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audio waveform.
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Typically, you'll want to use the derived class AudioThumbnail, which provides
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a concrete implementation.
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@see AudioThumbnail, AudioThumbnailCache
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@tags{Audio}
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*/
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class JUCE_API AudioThumbnailBase : public ChangeBroadcaster,
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public AudioFormatWriter::ThreadedWriter::IncomingDataReceiver
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{
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public:
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//==============================================================================
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AudioThumbnailBase() = default;
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~AudioThumbnailBase() override = default;
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//==============================================================================
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/** Clears and resets the thumbnail. */
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virtual void clear() = 0;
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/** Specifies the file or stream that contains the audio file.
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For a file, just call
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@code
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setSource (new FileInputSource (file))
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@endcode
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You can pass a nullptr in here to clear the thumbnail.
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The source that is passed in will be deleted by this object when it is no longer needed.
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@returns true if the source could be opened as a valid audio file, false if this failed for
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some reason.
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*/
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virtual bool setSource (InputSource* newSource) = 0;
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/** Gives the thumbnail an AudioFormatReader to use directly.
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This will start parsing the audio in a background thread (unless the hash code
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can be looked-up successfully in the thumbnail cache). Note that the reader
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object will be held by the thumbnail and deleted later when no longer needed.
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The thumbnail will actually keep hold of this reader until you clear the thumbnail
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or change the input source, so the file will be held open for all this time. If
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you don't want the thumbnail to keep a file handle open continuously, you
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should use the setSource() method instead, which will only open the file when
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it needs to.
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*/
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virtual void setReader (AudioFormatReader* newReader, int64 hashCode) = 0;
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//==============================================================================
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/** Reloads the low res thumbnail data from an input stream.
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This is not an audio file stream! It takes a stream of thumbnail data that would
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previously have been created by the saveTo() method.
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@see saveTo
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*/
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virtual bool loadFrom (InputStream& input) = 0;
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/** Saves the low res thumbnail data to an output stream.
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The data that is written can later be reloaded using loadFrom().
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@see loadFrom
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*/
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virtual void saveTo (OutputStream& output) const = 0;
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//==============================================================================
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/** Returns the number of channels in the file. */
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virtual int getNumChannels() const noexcept = 0;
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/** Returns the length of the audio file, in seconds. */
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virtual double getTotalLength() const noexcept = 0;
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/** Draws the waveform for a channel.
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The waveform will be drawn within the specified rectangle, where startTime
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and endTime specify the times within the audio file that should be positioned
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at the left and right edges of the rectangle.
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The waveform will be scaled vertically so that a full-volume sample will fill
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the rectangle vertically, but you can also specify an extra vertical scale factor
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with the verticalZoomFactor parameter.
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*/
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virtual void drawChannel (Graphics& g,
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const Rectangle<int>& area,
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double startTimeSeconds,
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double endTimeSeconds,
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int channelNum,
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float verticalZoomFactor) = 0;
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/** Draws the waveforms for all channels in the thumbnail.
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This will call drawChannel() to render each of the thumbnail's channels, stacked
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above each other within the specified area.
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@see drawChannel
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*/
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virtual void drawChannels (Graphics& g,
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const Rectangle<int>& area,
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double startTimeSeconds,
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double endTimeSeconds,
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float verticalZoomFactor) = 0;
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/** Returns true if the low res preview is fully generated. */
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virtual bool isFullyLoaded() const noexcept = 0;
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/** Returns the number of samples that have been set in the thumbnail. */
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virtual int64 getNumSamplesFinished() const noexcept = 0;
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/** Returns the highest level in the thumbnail.
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Note that because the thumb only stores low-resolution data, this isn't
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an accurate representation of the highest value, it's only a rough approximation.
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*/
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virtual float getApproximatePeak() const = 0;
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/** Reads the approximate min and max levels from a section of the thumbnail.
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The lowest and highest samples are returned in minValue and maxValue, but obviously
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because the thumb only stores low-resolution data, these numbers will only be a rough
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approximation of the true values.
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*/
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virtual void getApproximateMinMax (double startTime, double endTime, int channelIndex,
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float& minValue, float& maxValue) const noexcept = 0;
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/** Returns the hash code that was set by setSource() or setReader(). */
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virtual int64 getHashCode() const = 0;
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};
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} // namespace juce
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