Handling User Actions in Java Make barcode standards 128 in Java Handling User Actions

Handling User Actions generate, create code 128 barcode none on java projects Use Mobile Phone to Scan 1D and 2D Barcodes Printing Images sidebar discussion of it until later . The technique it uses is shown in the Printing Images sidebar, and coverage of the filePrint() method itself is in 13 (from page 400), where we also discuss approaches to printing documents in general. The only le action we have not reviewed is the le quit action.

This action is connected to the main window s close() method, which in turn causes a close event to be put on the event queue. We provided a reimplementation of the closeEvent() handler in which we made sure the user had the chance to save unsaved changes, using a call to okToContinue(), and where we saved the application s settings..

363. closeEvent(). 185 . Handling Edit Actions Most of the functionality of jboss code 128 code set c the le actions was provided by the MainWindow subclass itself. The only work passed on was the image loading and saving, which the QImage instance variable was required to do. This particular division of responsibilities between a main window and the data structure that holds the data is very common.

The main window handles the high-level le new, open, save, and recently used les functionality, and the data structure handles loading and saving. It is also common for most, or even all, of the editing functionality to be provided either by the view widget or by the data structure. In the Image Changer application, all the data manipulation is handled by the data structure (the image QImage), and the presentation of the data is handled by the data viewer (the imageLabel QLabel).

Again, this is a very common separation of responsibilities. In this section, we will review most of the edit actions, omitting a couple that are almost identical to ones that are shown. We will be quite brief here, since the functionality is speci c to the Image Changer application.

. def editInvert(self, on): if self.image.isNull(): return self.

image.invertPixels() self.showImage() self.

dirty = True self.updateStatus("Inverted" if on else "Uninverted"). If the user invokes the edi code-128b for Java t invert action, it will be checked (or unchecked). In either case, we simply invert the image s pixels using the functionality provided by QImage, show the changed image, set the dirty ag, and call updateStatus() so that the status bar brie y shows the action that was performed, and an additional item is added to the log. The editSwapRedAndBlue() method (not shown) is the same except that it uses the QImage.

rgbSwapped() method, and it has different status text.. 6. Main Windows def editMirrorHorizontal(sel barcode 128 for Java f, on): if self.image.isNull(): return self.

image = self.image.mirrored(True, False) self.

showImage() self.mirroredhorizontally = not self.mirroredhorizontally self.

dirty = True self.updateStatus("Mirrored Horizontally" \ if on else "Unmirrored Horizontally"). This method is structurally the same as editInvert() and editSwapRedAndBlue(). The QImage.mirrored() method takes two Boolean ags, the rst for horizontal mirroring and the second for vertical mirroring.

In the Image Changer application, we have deliberately restricted what mirroring is allowed, so users can only have no mirroring, vertical mirroring, or horizontal mirroring, but not a combination of vertical and horizontal. We also keep an instance variable that keeps track of whether the image is horizontally mirrored. The editMirrorVertical() method, not shown, is virtually identical.

. def editUnMirror(self, on): ANSI/AIM Code 128 for Java if self.image.isNull(): return if self.

mirroredhorizontally: self.editMirrorHorizontal(False) if self.mirroredvertically: self.

editMirrorVertical(False). This method switches off whi chever mirroring is in force, or does nothing if the image is not mirrored. It does not set the dirty ag or update the status: It leaves that for editMirrorHorizontal() or editMirrorVertical(), if it calls either of them. The application provides two means by which the user can change the zoom factor.

They can interact with the zoom spinbox in the toolbar its valueChanged() signal is connected to the showImage() slot that we will review shortly or they can invoke the edit zoom action in the Edit menu. If they use the edit zoom action, the editZoom() method is called..

def editZoom(self): if self. ANSI/AIM Code 128 for Java image.isNull(): return percent, ok = QInputDialog.

getInteger(self, "Image Changer - Zoom", "Percent:", self.zoomSpinBox.value(), 1, 400) if ok: self.

Copyright © . All rights reserved.