HippoCanvas: Difference between revisions
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== Deprecation Warning == |
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Hippocanvas is sort of deprecated. Initially, hippocanvas was to be the basic building block for all Activities, but it proved too immature to be used everywhere. Instead activity developers are encouraged to use the standard GTK components. However, hippocanvas does provide some features that are difficult or impossible with standard GTK, as used by Chat and a few other Sugar elements. Therefore, it is included in the build. |
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-Benjinam M. Schwartz |
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== Introduction == |
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HippoCanvas is a generic user interface element that can draw [[Cairo]] graphics, respond to key and mouse events, and lay out other widgets. It is currently used to implement a number of [[Sugar]]'s custom widgets (toolbars, rounded buttons, etc.) and to lay out the screen. |
HippoCanvas is a generic user interface element that can draw [[Cairo]] graphics, respond to key and mouse events, and lay out other widgets. It is currently used to implement a number of [[Sugar]]'s custom widgets (toolbars, rounded buttons, etc.) and to lay out the screen. |
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On the OLPC, HippoCanvas is a [[GTK]] widget and it can contain other GTK widgets, so the programmer can freely combine HippoCanvas and other widgets. While Sugar does not require that activities be written using HippoCanvas, those that do can look more visually consistent with other activities. |
On the OLPC, HippoCanvas, aka hippo, is a [[GTK]] widget and it can contain other GTK widgets, so the programmer can freely combine HippoCanvas and other widgets. While Sugar does not require that activities be written using HippoCanvas, those that do can look more visually consistent with other activities. |
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== Rationale == |
== Rationale == |
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HippoCanvas was originally designed to be a cross-platform UI layer built on top of other windowing systems. It is used in Sugar to work around deficiencies GTK's layout system. [http://log.ometer.com/2006-10.html#14] HippoCanvas also makes it easier to prototype custom widgets, and its Python interface can be somewhat simpler than native GTK widgets. |
HippoCanvas was originally designed to be a cross-platform UI layer built on top of other windowing systems. It is used in Sugar to work around deficiencies in GTK's layout system. [http://log.ometer.com/2006-10.html#14] HippoCanvas also makes it easier to prototype custom widgets, and its Python interface can be somewhat simpler than native GTK widgets. |
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[http://www.vrplumber.com/sugar-docs/hippo.html Hippo PyDoc] |
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= Classes and Interfaces = |
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== Canvas object == |
== Canvas object == |
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Derives from GtkContainer. This is a GTK widget that hosts a root CanvasItem. |
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== CanvasBox object == |
== CanvasBox object == |
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Derives from GObject, implements CanvasItem, CanvasContext. |
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== CanvasWidget object == |
== CanvasWidget object == |
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Derives from CanvasBox. |
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== CanvasImage object == |
== CanvasImage object == |
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Derives from CanvasBox. |
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== CanvasText object == |
== CanvasText object == |
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Derives from CanvasBox. |
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== CanvasLink object == |
== CanvasLink object == |
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Derives from CanvasText. |
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= Enumerations = |
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== PackFlags enumeration == |
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== CascadeMode enumeration == |
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== StockColor enumeration == |
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== CanvasPointer enumeration == |
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== ItemAlignment enumeration == |
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== CanvasSizeMode enumeration == |
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== ScrollbarPolicy enumeration == |
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== EventType enumeration == |
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== MotionDetail enumeration == |
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== Key enumeration == |
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== Orientation enumeration == |
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== Side enumeration == |
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== Gravity enumeration == |
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= Internal objects = |
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== Event object == |
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Encapsulates information about a mouse action or keypress. It is currently only used internally. |
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== Rectangle object == |
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Describes a rectangle on the screen in integer coordinates. It is currently only used internally. |
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Fields: |
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* x |
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* y |
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* width |
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* height |
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Methods: |
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* rectangle.intersect(rect2, dest) |
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* rectangle.equals(rect2) => boolean |
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= Links = |
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* [http://log.ometer.com/2006-10.html#14 A blog entry] on the rationale for HippoCanvas. |
* [http://log.ometer.com/2006-10.html#14 A blog entry] on the rationale for HippoCanvas. |
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Latest revision as of 18:12, 20 December 2007
Deprecation Warning
Hippocanvas is sort of deprecated. Initially, hippocanvas was to be the basic building block for all Activities, but it proved too immature to be used everywhere. Instead activity developers are encouraged to use the standard GTK components. However, hippocanvas does provide some features that are difficult or impossible with standard GTK, as used by Chat and a few other Sugar elements. Therefore, it is included in the build. -Benjinam M. Schwartz
Introduction
HippoCanvas is a generic user interface element that can draw Cairo graphics, respond to key and mouse events, and lay out other widgets. It is currently used to implement a number of Sugar's custom widgets (toolbars, rounded buttons, etc.) and to lay out the screen.
On the OLPC, HippoCanvas, aka hippo, is a GTK widget and it can contain other GTK widgets, so the programmer can freely combine HippoCanvas and other widgets. While Sugar does not require that activities be written using HippoCanvas, those that do can look more visually consistent with other activities.
Rationale
HippoCanvas was originally designed to be a cross-platform UI layer built on top of other windowing systems. It is used in Sugar to work around deficiencies in GTK's layout system. [1] HippoCanvas also makes it easier to prototype custom widgets, and its Python interface can be somewhat simpler than native GTK widgets.
PyDoc
Classes and Interfaces
Canvas object
Derives from GtkContainer. This is a GTK widget that hosts a root CanvasItem.
CanvasItem interface
CanvasContext interface
CanvasBox object
Derives from GObject, implements CanvasItem, CanvasContext.
CanvasWidget object
Derives from CanvasBox.
CanvasImage object
Derives from CanvasBox.
CanvasText object
Derives from CanvasBox.
CanvasLink object
Derives from CanvasText.
Enumerations
PackFlags enumeration
CascadeMode enumeration
StockColor enumeration
CanvasPointer enumeration
ItemAlignment enumeration
CanvasSizeMode enumeration
ScrollbarPolicy enumeration
EventType enumeration
MotionDetail enumeration
Key enumeration
Orientation enumeration
Side enumeration
Gravity enumeration
Internal objects
Event object
Encapsulates information about a mouse action or keypress. It is currently only used internally.
Rectangle object
Describes a rectangle on the screen in integer coordinates. It is currently only used internally.
Fields:
- x
- y
- width
- height
Methods:
- rectangle.intersect(rect2, dest)
- rectangle.equals(rect2) => boolean
Links
- A blog entry on the rationale for HippoCanvas.
- A mailing list post about HippoCanvas.
- HippoCanvas source v. 0.2.6