Images (for developers) - Revision history

Blu256: Remove WIP marking (still has a few TODOs)

2023-11-25T22:05:08Z

Remove WIP marking (still has a few TODOs)

Blu256: /* TQImage::save(...) */ a nice section pretitle

2023-11-25T21:57:23Z

TQImage::save(...): a nice section pretitle

Blu256: Add section on saving images

2023-11-25T21:56:53Z

Add section on saving images

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Blu256: Add layout of page

2023-11-25T20:58:11Z

Add layout of page

Blu256: Switch to the new TDE class template

2023-11-25T20:55:17Z

Switch to the new TDE class template

Blu256: Added basic instructions for loading and displaying images

2023-11-25T20:48:07Z

Added basic instructions for loading and displaying images

Blu256: Started writing

2023-11-25T20:28:28Z

Started writing

New page

{{WIP|Blu256}}

Working with images is an important part of a graphical application, whether it's a simple application or a complex graphical suite. In TQt/TDE, this can be as simple as learning to use a few classes. This guide aims to be a good guide for developers who want to work with TQt/TDE.

__TOC__

== Image classes ==
* {{TQt class|TQPixmap}} is one of the two basic image classes provided by TQt.
: It is, essentially, a paint device, so it is optimized for drawing. You'll see this class used a lot (more than TQImage) because of this quality.
* {{TQt class|TQImage}} is the other basic image class.
: According to the API docs, it is "a hardware-independent pixmap representation" and it is optimized for I/O operations and direct pixel access and manipulation.
* {{TQt class|TQIconSet}} is a helper class for icons.
: Compared to the basic image classes, this class does not represent a single image, but a ''set'' of images which correspond to an icon. A folder icon can come in different sizes (a different image file corresponds to each size), but it is still considered to be the same icon.

[[Category: Developers]]

← Older revision		Revision as of 22:05, 25 November 2023
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	{{WIP\|Blu256}}

	Working with images is an important part of a graphical application, whether it's a simple application or a complex graphical suite. In TQt/TDE, this can be as simple as learning to use a few classes. This guide aims to be a good guide for developers who want to work with TQt/TDE.		Working with images is an important part of a graphical application, whether it's a simple application or a complex graphical suite. In TQt/TDE, this can be as simple as learning to use a few classes. This guide aims to be a good guide for developers who want to work with TQt/TDE.

@@ Line 59: / Line 59: @@
 Let's start with the basics.
-==== <tt>TQImage::save(...)</tt> ====
+==== The Foundation: <tt>TQImage::save(...)</tt> ====
 {{TQt class|TQImage}} provides a convenient <code>save(const TQString &fileName, const char *format, int quality = -1)</code> method which, as you can tell, saves the image in memory to the selected destination (<tt>fileName</tt>).

@@ Line 15: / Line 15: @@
 Usually you won't need more advanced classes.
-== Loading an image ==
+== Basic usage ==
+=== Loading an image ===
 The simplest way to load an image is to use the constructor of the {{TQt class|TQPixmap}} class with the path of the file you want to load. If the file is located in one of your application paths (e.g. the <tt>share</tt> folder) use the {{TDE class|tdelibs|tdecore|TDEStandardDirs}} class.
@@ Line 24: / Line 25: @@
 </syntaxhighlight>
-== Displaying an image ==
+=== Displaying an image ===
 Images can be used in quite a few widgets, including labels, text views and buttons. These widgets offer constructors and/or functions where you can pass an image as an argument (usually as a {{TQt class|TQPixmap}} or a {{TQt class|TQIconSet}}.
@@ Line 35: / Line 36: @@
 If you want to display an image as standalone, you first need a widget where you will display it. Usually, a {{TQt class|TQLabel}} should be enough.
+=== Applying effects ===
+{{TODO}}
+== Advanced usage ==
+=== Saving an image ===
+{{TODO}}
+==== Using KImageIO ====
+{{TODO}}
+== TDE Developers' usage ==
+=== Adding image format support ===
+{{TODO}}
 [[Category: Developers]]

@@ Line 16: / Line 16: @@
 == Loading an image ==
-The simplest way to load an image is to use the constructor of the {{TQt class|TQPixmap}} class with the path of the file you want to load. If the file is located in one of your application paths (e.g. the <tt>share</tt> folder) use the [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEStandardDirs.html TDEStandardDirs] class.
+The simplest way to load an image is to use the constructor of the {{TQt class|TQPixmap}} class with the path of the file you want to load. If the file is located in one of your application paths (e.g. the <tt>share</tt> folder) use the {{TDE class|tdelibs|tdecore|TDEStandardDirs}} class.
-If you want to load an icon, the simplest (and by far the most preferred) way to do so is via the  [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEIconLoader.html TDEIconLoader] class. For TDE applications you don't even have to explicitly initialize this object. You can access a TDEIconLoader instance from the [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEApplication.html TDEApplication] class. The TDEIconLoader class makes sure that recommended settings are used for the kind of icon you are loading, so you usually need to provide a `group` parameter of type [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEIcon.html#a8d521faaf8f00ecbe33314a08d386f91 TDEIcon::Group] which defines the type of icon that you are loading and will decide its size and whether any effects will be applied to it. For example, to load a folder icon with the default settings for a toolbar icon:
+If you want to load an icon, the simplest (and by far the most preferred) way to do so is via the  {{TDE class|tdelibs|tdecore|TDEIconLoader}} class. For TDE applications you don't even have to explicitly initialize this object. You can access an instance of this class through the `kapp` pointer of the {{TDE class|tdelibs|tdecore|TDEApplication}} class. The icon loader class makes sure that recommended settings are used for the kind of icon you are loading, so you usually need to provide a `group` parameter of type [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEIcon.html#a8d521faaf8f00ecbe33314a08d386f91 TDEIcon::Group] which defines the type of icon that you are loading and will decide its size and whether any effects will be applied to it. For example, to load a folder icon with the default settings for a toolbar icon:
 <syntaxhighlight lang="c++">

@@ Line 12: / Line 12: @@
 * {{TQt class|TQIconSet}} is a helper class for icons.
 : Compared to the basic image classes, this class does not represent a single image, but a ''set'' of images which correspond to an icon. A folder icon can come in different sizes (a different image file corresponds to each size), but it is still considered to be the same icon.
+Usually you won't need more advanced classes.
+== Loading an image ==
+The simplest way to load an image is to use the constructor of the {{TQt class|TQPixmap}} class with the path of the file you want to load. If the file is located in one of your application paths (e.g. the <tt>share</tt> folder) use the [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEStandardDirs.html TDEStandardDirs] class.
+If you want to load an icon, the simplest (and by far the most preferred) way to do so is via the  [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEIconLoader.html TDEIconLoader] class. For TDE applications you don't even have to explicitly initialize this object. You can access a TDEIconLoader instance from the [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEApplication.html TDEApplication] class. The TDEIconLoader class makes sure that recommended settings are used for the kind of icon you are loading, so you usually need to provide a `group` parameter of type [http://trinitydesktop.org/docs/trinity/tdelibs/tdecore/html/classTDEIcon.html#a8d521faaf8f00ecbe33314a08d386f91 TDEIcon::Group] which defines the type of icon that you are loading and will decide its size and whether any effects will be applied to it. For example, to load a folder icon with the default settings for a toolbar icon:
+<syntaxhighlight lang="c++">
+TQPixmap icon = kapp->iconLoader()->loadIcon("folder", TDEIcon::Toolbar);
+</syntaxhighlight>
+== Displaying an image ==
+Images can be used in quite a few widgets, including labels, text views and buttons. These widgets offer constructors and/or functions where you can pass an image as an argument (usually as a {{TQt class|TQPixmap}} or a {{TQt class|TQIconSet}}.
+The following example creates a push button with a folder icon from the icon theme:
+<syntaxhighlight lang="c++">
+TQIconSet icon = kapp->iconLoader()->loadIconSet("folder", TDEIcon::Toolbar);
+TQPushButton *button = new TQPushButton(icon, i18n("Open folder..."), this);
+</syntaxhighlight>
+If you want to display an image as standalone, you first need a widget where you will display it. Usually, a {{TQt class|TQLabel}} should be enough.
 [[Category: Developers]]