QGIS API Documentation
3.0.2-Girona (307d082)
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QgsTask task which performs a QgsRasterFileWriter layer saving operation as a background task. More...
#include <qgsrasterfilewritertask.h>
Signals | |
void | errorOccurred (int error) |
Emitted when an error occurs which prevented the file being written (or if the task is canceled). More... | |
void | writeComplete (const QString &outputUrl) |
Emitted when writing the layer is successfully completed. More... | |
Signals inherited from QgsTask | |
void | begun () |
Will be emitted by task to indicate its commencement. More... | |
void | progressChanged (double progress) |
Will be emitted by task when its progress changes. More... | |
void | statusChanged (int status) |
Will be emitted by task when its status changes. More... | |
void | taskCompleted () |
Will be emitted by task to indicate its successful completion. More... | |
void | taskTerminated () |
Will be emitted by task if it has terminated for any reason other then completion (e.g., when a task has been canceled or encountered an internal error). More... | |
Public Member Functions | |
QgsRasterFileWriterTask (const QgsRasterFileWriter &writer, QgsRasterPipe *pipe, int columns, int rows, const QgsRectangle &outputExtent, const QgsCoordinateReferenceSystem &crs) | |
Constructor for QgsRasterFileWriterTask. More... | |
void | cancel () override |
Notifies the task that it should terminate. More... | |
Public Member Functions inherited from QgsTask | |
QgsTask (const QString &description=QString(), QgsTask::Flags flags=AllFlags) | |
Constructor for QgsTask. More... | |
~QgsTask () override | |
void | addSubTask (QgsTask *subTask, const QgsTaskList &dependencies=QgsTaskList(), SubTaskDependency subTaskDependency=SubTaskIndependent) |
Adds a subtask to this task. More... | |
bool | canCancel () const |
Returns true if the task can be canceled. More... | |
QList< QgsMapLayer *> | dependentLayers () const |
Returns the list of layers on which the task depends. More... | |
QString | description () const |
Returns the task's description. More... | |
Flags | flags () const |
Returns the flags associated with the task. More... | |
void | hold () |
Places the task on hold. More... | |
bool | isActive () const |
Returns true if the task is active, ie it is not complete and has not been canceled. More... | |
double | progress () const |
Returns the task's progress (between 0.0 and 100.0) More... | |
void | setDependentLayers (const QList< QgsMapLayer *> &dependentLayers) |
Sets a list of layers on which the task depends. More... | |
TaskStatus | status () const |
Returns the current task status. More... | |
void | unhold () |
Releases the task from being held. More... | |
bool | waitForFinished (unsigned long timeout=30000) |
Blocks the current thread until the task finishes or a maximum of timeout milliseconds. More... | |
Protected Member Functions | |
void | finished (bool result) override |
If the task is managed by a QgsTaskManager, this will be called after the task has finished (whether through successful completion or via early termination). More... | |
bool | run () override |
Performs the task's operation. More... | |
Protected Member Functions inherited from QgsTask | |
bool | isCanceled () const |
Will return true if task should terminate ASAP. More... | |
Additional Inherited Members | |
Public Types inherited from QgsTask | |
enum | Flag { CanCancel = 1 << 1, AllFlags = CanCancel } |
Task flags. More... | |
enum | SubTaskDependency { SubTaskIndependent = 0, ParentDependsOnSubTask } |
Controls how subtasks relate to their parent task. More... | |
enum | TaskStatus { Queued, OnHold, Running, Complete, Terminated } |
Status of tasks. More... | |
Protected Slots inherited from QgsTask | |
void | setProgress (double progress) |
Sets the task's current progress. More... | |
QgsTask task which performs a QgsRasterFileWriter layer saving operation as a background task.
This can be used to save a raster layer out to a file without blocking the QGIS interface.
Definition at line 37 of file qgsrasterfilewritertask.h.
QgsRasterFileWriterTask::QgsRasterFileWriterTask | ( | const QgsRasterFileWriter & | writer, |
QgsRasterPipe * | pipe, | ||
int | columns, | ||
int | rows, | ||
const QgsRectangle & | outputExtent, | ||
const QgsCoordinateReferenceSystem & | crs | ||
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Constructor for QgsRasterFileWriterTask.
Takes a source writer, columns, rows, outputExtent and destination crs. Ownership of the pipe is transferred to the writer task, and will be deleted when the task completes.
Definition at line 21 of file qgsrasterfilewritertask.cpp.
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overridevirtual |
Notifies the task that it should terminate.
Calling this is not guaranteed to immediately end the task, rather it sets the isCanceled() flag which task subclasses can check and terminate their operations at an appropriate time. Any subtasks owned by this task will also be canceled. Derived classes must ensure that the base class implementation is called from any overridden version.
Reimplemented from QgsTask.
Definition at line 35 of file qgsrasterfilewritertask.cpp.
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signal |
Emitted when an error occurs which prevented the file being written (or if the task is canceled).
The writing error will be reported.
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overrideprotectedvirtual |
If the task is managed by a QgsTaskManager, this will be called after the task has finished (whether through successful completion or via early termination).
The result argument reflects whether the task was successfully completed or not. This method is always called from the main thread, so it is safe to create widgets and perform other operations which require the main thread. However, the GUI will be blocked for the duration of this method so tasks should avoid performing any lengthy operations here.
Reimplemented from QgsTask.
Definition at line 53 of file qgsrasterfilewritertask.cpp.
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overrideprotectedvirtual |
Performs the task's operation.
This method will be called when the task commences (ie via calling start() ), and subclasses should implement the operation they wish to perform in the background within this method.
A task must return a boolean value to indicate whether the task was completed successfully or terminated before completion.
Implements QgsTask.
Definition at line 41 of file qgsrasterfilewritertask.cpp.
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signal |
Emitted when writing the layer is successfully completed.
The outputUrl parameter indicates the file path for the written file(s).