Makes it easy to quickly draw scaled views of the waveform shape of an audio file. More...
#include <juce_AudioThumbnail.h>
Public Member Functions | |
AudioThumbnail (int sourceSamplesPerThumbnailSample, AudioFormatManager &formatManagerToUse, AudioThumbnailCache &cacheToUse) | |
Creates an audio thumbnail. More... | |
~AudioThumbnail () override | |
Destructor. More... | |
void | addBlock (int64 sampleNumberInSource, const AudioBuffer< float > &newData, int startOffsetInBuffer, int numSamples) override |
Adds a block of level data to the thumbnail. More... | |
void | addChangeListener (ChangeListener *listener) |
Registers a listener to receive change callbacks from this broadcaster. More... | |
void | clear () override |
Clears and resets the thumbnail. More... | |
void | dispatchPendingMessages () |
If a change message has been sent but not yet dispatched, this will call sendSynchronousChangeMessage() to make the callback immediately. More... | |
void | drawChannel (Graphics &g, const Rectangle< int > &area, double startTimeSeconds, double endTimeSeconds, int channelNum, float verticalZoomFactor) override |
Draws the waveform for a channel. More... | |
void | drawChannels (Graphics &g, const Rectangle< int > &area, double startTimeSeconds, double endTimeSeconds, float verticalZoomFactor) override |
Draws the waveforms for all channels in the thumbnail. More... | |
void | getApproximateMinMax (double startTime, double endTime, int channelIndex, float &minValue, float &maxValue) const noexcept override |
Reads the approximate min and max levels from a section of the thumbnail. More... | |
float | getApproximatePeak () const override |
Returns the highest level in the thumbnail. More... | |
int64 | getHashCode () const override |
Returns the hash code that was set by setSource() or setReader(). More... | |
int | getNumChannels () const noexcept override |
Returns the number of channels in the file. More... | |
int64 | getNumSamplesFinished () const noexcept override |
Returns the number of samples that have been set in the thumbnail. More... | |
double | getProportionComplete () const noexcept |
Returns a value between 0 and 1 to indicate the progress towards loading the entire file. More... | |
double | getTotalLength () const noexcept override |
Returns the length of the audio file, in seconds. More... | |
bool | isFullyLoaded () const noexcept override |
Returns true if the low res preview is fully generated. More... | |
bool | loadFrom (InputStream &input) override |
Reloads the low res thumbnail data from an input stream. More... | |
void | removeAllChangeListeners () |
Removes all listeners from the list. More... | |
void | removeChangeListener (ChangeListener *listener) |
Unregisters a listener from the list. More... | |
void | reset (int numChannels, double sampleRate, int64 totalSamplesInSource=0) override |
Resets the thumbnail, ready for adding data with the specified format. More... | |
void | saveTo (OutputStream &output) const override |
Saves the low res thumbnail data to an output stream. More... | |
void | sendChangeMessage () |
Causes an asynchronous change message to be sent to all the registered listeners. More... | |
void | sendSynchronousChangeMessage () |
Sends a synchronous change message to all the registered listeners. More... | |
void | setReader (AudioFormatReader *newReader, int64 hashCode) override |
Gives the thumbnail an AudioFormatReader to use directly. More... | |
bool | setSource (InputSource *newSource) override |
Specifies the file or stream that contains the audio file. More... | |
Private Member Functions | |
void | callListeners () |
void | clearChannelData () |
void | createChannels (int length) |
bool | setDataSource (LevelDataSource *newSource) |
void | setLevels (const MinMaxValue *const *values, int thumbIndex, int numChans, int numValues) |
Private Attributes | |
std::atomic< bool > | anyListeners { false } |
ChangeBroadcasterCallback | broadcastCallback |
AudioThumbnailCache & | cache |
ListenerList< ChangeListener > | changeListeners |
OwnedArray< ThumbData > | channels |
AudioFormatManager & | formatManagerToUse |
CriticalSection | lock |
int32 | numChannels = 0 |
int64 | numSamplesFinished = 0 |
double | sampleRate = 0 |
int32 | samplesPerThumbSample = 0 |
std::unique_ptr< LevelDataSource > | source |
int64 | totalSamples { 0 } |
std::unique_ptr< CachedWindow > | window |
Makes it easy to quickly draw scaled views of the waveform shape of an audio file.
To use this class, just create an AudioThumbnail class for the file you want to draw, call setSource to tell it which file or resource to use, then call drawChannel() to draw it.
The class will asynchronously scan the wavefile to create its scaled-down view, so you should make your UI repaint itself as this data comes in. To do this, the AudioThumbnail is a ChangeBroadcaster, and will broadcast a message when its listeners should repaint themselves.
The thumbnail stores an internal low-res version of the wave data, and this can be loaded and saved to avoid having to scan the file again.
@tags{Audio}
juce::AudioThumbnail::AudioThumbnail | ( | int | sourceSamplesPerThumbnailSample, |
AudioFormatManager & | formatManagerToUse, | ||
AudioThumbnailCache & | cacheToUse | ||
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Creates an audio thumbnail.
sourceSamplesPerThumbnailSample | when creating a stored, low-res version of the audio data, this is the scale at which it should be done. (This number is the number of original samples that will be averaged for each low-res sample) |
formatManagerToUse | the audio format manager that is used to open the file |
cacheToUse | an instance of an AudioThumbnailCache - this provides a background thread and storage that is used to by the thumbnail, and the cache object can be shared between multiple thumbnails |
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override |
Destructor.
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overridevirtual |
Adds a block of level data to the thumbnail.
Call reset() before using this, to tell the thumbnail about the data format.
Implements juce::AudioFormatWriter::ThreadedWriter::IncomingDataReceiver.
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inherited |
Registers a listener to receive change callbacks from this broadcaster.
Trying to add a listener that's already on the list will have no effect.
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privateinherited |
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overridevirtual |
Clears and resets the thumbnail.
Implements juce::AudioThumbnailBase.
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inherited |
If a change message has been sent but not yet dispatched, this will call sendSynchronousChangeMessage() to make the callback immediately.
For thread-safety reasons, you must only call this method on the main message thread.
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overridevirtual |
Draws the waveform for a channel.
The waveform will be drawn within the specified rectangle, where startTime and endTime specify the times within the audio file that should be positioned at the left and right edges of the rectangle.
The waveform will be scaled vertically so that a full-volume sample will fill the rectangle vertically, but you can also specify an extra vertical scale factor with the verticalZoomFactor parameter.
Implements juce::AudioThumbnailBase.
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overridevirtual |
Draws the waveforms for all channels in the thumbnail.
This will call drawChannel() to render each of the thumbnail's channels, stacked above each other within the specified area.
Implements juce::AudioThumbnailBase.
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overridevirtualnoexcept |
Reads the approximate min and max levels from a section of the thumbnail.
The lowest and highest samples are returned in minValue and maxValue, but obviously because the thumb only stores low-resolution data, these numbers will only be a rough approximation of the true values.
Implements juce::AudioThumbnailBase.
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overridevirtual |
Returns the highest level in the thumbnail.
Note that because the thumb only stores low-resolution data, this isn't an accurate representation of the highest value, it's only a rough approximation.
Implements juce::AudioThumbnailBase.
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overridevirtual |
Returns the hash code that was set by setSource() or setReader().
Implements juce::AudioThumbnailBase.
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overridevirtualnoexcept |
Returns the number of channels in the file.
Implements juce::AudioThumbnailBase.
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overridevirtualnoexcept |
Returns the number of samples that have been set in the thumbnail.
Implements juce::AudioThumbnailBase.
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noexcept |
Returns a value between 0 and 1 to indicate the progress towards loading the entire file.
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overridevirtualnoexcept |
Returns the length of the audio file, in seconds.
Implements juce::AudioThumbnailBase.
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overridevirtualnoexcept |
Returns true if the low res preview is fully generated.
Implements juce::AudioThumbnailBase.
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overridevirtual |
Reloads the low res thumbnail data from an input stream.
This is not an audio file stream! It takes a stream of thumbnail data that would previously have been created by the saveTo() method.
Implements juce::AudioThumbnailBase.
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Removes all listeners from the list.
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inherited |
Unregisters a listener from the list.
If the listener isn't on the list, this won't have any effect.
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overridevirtual |
Resets the thumbnail, ready for adding data with the specified format.
If you're going to generate a thumbnail yourself, call this before using addBlock() to add the data.
Implements juce::AudioFormatWriter::ThreadedWriter::IncomingDataReceiver.
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overridevirtual |
Saves the low res thumbnail data to an output stream.
The data that is written can later be reloaded using loadFrom().
Implements juce::AudioThumbnailBase.
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inherited |
Causes an asynchronous change message to be sent to all the registered listeners.
The message will be delivered asynchronously by the main message thread, so this method will return immediately. To call the listeners synchronously use sendSynchronousChangeMessage().
Referenced by juce::SelectedItemSet< SelectableItemType >::changed().
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inherited |
Sends a synchronous change message to all the registered listeners.
This will immediately call all the listeners that are registered. For thread-safety reasons, you must only call this method on the main message thread.
Referenced by juce::SelectedItemSet< SelectableItemType >::changed().
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Gives the thumbnail an AudioFormatReader to use directly.
This will start parsing the audio in a background thread (unless the hash code can be looked-up successfully in the thumbnail cache). Note that the reader object will be held by the thumbnail and deleted later when no longer needed. The thumbnail will actually keep hold of this reader until you clear the thumbnail or change the input source, so the file will be held open for all this time. If you don't want the thumbnail to keep a file handle open continuously, you should use the setSource() method instead, which will only open the file when it needs to.
Implements juce::AudioThumbnailBase.
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overridevirtual |
Specifies the file or stream that contains the audio file.
For a file, just call
You can pass a nullptr in here to clear the thumbnail. The source that is passed in will be deleted by this object when it is no longer needed.
Implements juce::AudioThumbnailBase.
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