This class encapsulates the concept of a platform-dependent bitmap,
either monochrome, colour, or colour with alpha channel (transparency)
support.
wxRuby provides two classes for handling images. Bitmap is
used for drawing upon the screen, for example using a
DeviceContext. The other class Image cannot be
drawn directly upon the screen, but supports a variety of image
manipulation functions such as rescaling, blurring, and directly
manipulating pixels.
Note that because this class wraps a platform-specific GUI resource, you
shouldn’t create instances of it until the app is running; ie until
after you have called App#main_loop or App.run.
Objects:
NullBitmap
Bitmap overview,
supported bitmap file formats,
DC#blit,
Icon, Cursor, Image,
MemoryDC
The two main constructors for this class are used to create a blank
bitmap, or to load a bitmap from a file. from_image
can be used to convert an Image into a bitmap.
Creates a new bitmap. A depth of -1 indicates the depth of the current screen
or visual. Some platforms only support 1 for monochrome and -1 for the current
colour setting.
Loads a bitmap from a file or resource.
The following constructors are not fully supported or tested:
Bitmap.new(%(arg-type)% data, Integer type, Integer width, Integer height, Integer depth = -1)Creates a bitmap from the given data which is interpreted in platform-dependent
manner.
Creates a bitmap from an array of bits.
You should only use this function for monochrome bitmaps (depth 1) in
portable programs: in this case the bits parameter should contain an XBM
image.
For other bit depths, the behaviour is platform dependent: under Windows, the
data is passed without any changes to the underlying CreateBitmap()
API.
Under other platforms, only monochrome bitmaps may be created using this
constructor and Image should be used for creating colour
bitmaps from static data.
Creates a bitmap from XPM data.
BITMAP_TYPE_BMP | Load a Windows bitmap file. |
BITMAP_TYPE_BMP_RESOURCE | Load a Windows bitmap resource from the executable. Windows only. |
BITMAP_TYPE_PICT_RESOURCE | Load a PICT image resource from the executable. Mac OS only. |
BITMAP_TYPE_GIF | Load a GIF bitmap file. |
BITMAP_TYPE_XBM | Load an X bitmap file. |
BITMAP_TYPE_XPM | Load an XPM bitmap file. |
The validity of these flags depends on the platform and Widgets
configuration. If all possible Widgets settings are used, the Windows
platform supports BMP file, BMP resource, XPM data, and XPM. Under GTK,
the available formats are BMP file, XPM data, XPM file, and PNG file.
Under Motif, the available formats are XBM data, XBM file, XPM data, XPM
file.
In addition, Bitmap can read all formats that Image can,
which currently include BITMAP_TYPE_JPEG, BITMAP_TYPE_TIF,
BITMAP_TYPE_PNG, BITMAP_TYPE_GIF, BITMAP_TYPE_PCX, and
BITMAP_TYPE_PNM. Of course, you must have Image handlers loaded. *
img Platform-independent Image object.
Under Windows, type defaults to BITMAP_TYPE_BMP_RESOURCE. Under X,
type defaults to BITMAP_TYPE_XPM.
Creates bitmap object from the image. This has to be done
to actually display an image as you cannot draw an image directly on a window.
The resulting bitmap will use the provided colour depth (or that of the
current system if depth is -1) which entails that a colour reduction has
to take place.
When in 8-bit mode (PseudoColour mode), the GTK port will use a color cube created
on program start-up to look up colors. This ensures a very fast conversion, but
the image quality won’t be perfect (and could be better for photo images using more
sophisticated dithering algorithms).
On Windows, if there is a palette present (set with SetPalette), it will be used when
creating the Bitmap (most useful in 8-bit display mode). On other platforms,
the palette is currently ignored.
Destroys the Bitmap object and possibly the underlying bitmap data.
Because reference counting is used, the bitmap may not actually be
destroyed at this point – only when the reference count is zero will the
data be deleted.
If the application omits to delete the bitmap explicitly, the bitmap will be
destroyed automatically by Widgets when the application exits.
Do not delete a bitmap that is selected into a memory device context,
for example during a call to draw .
Creates an image from a platform-dependent bitmap. This preserves
mask information so that bitmaps and images can be converted back
and forth without loss in that respect.
Creates the bitmap from an icon.
Creates a fresh bitmap. If the final argument is omitted, the display depth of
the screen is used.
Creates a bitmap from the given data, which can be of arbitrary type.
true if the call succeeded, false otherwise.
The first form works on all platforms. The portability of the second form depends on the
type of data.
Allows drawing directly onto a Bitmap. Accepts a block which will be
passed a MemoryDC device context, which can be used to
draw lines, shapes and text upon a bitmap. See DC for the full
range of drawing methods that are available.
Using this call ensures that the device context is properly set up for
use before drawing starts, and disposed of when drawing is
finished. It’s recommended you use this draw method rather than
instantiating MemoryDC directly.
Gets the colour depth of the bitmap. A value of 1 indicates a
monochrome bitmap.
Gets the height of the bitmap in pixels.
Gets the associated palette (if any) which may have been loaded from a file
or set for the bitmap.
Gets the associated mask (if any) which may have been loaded from a file
or set for the bitmap.
Gets the width of the bitmap in pixels.
Returns a sub bitmap of the current one as long as the rect belongs entirely to
the bitmap. This function preserves bit depth and mask information.
Loads a bitmap from a file or resource.
BITMAP_TYPE_BMP | Load a Windows bitmap file. |
BITMAP_TYPE_BMP_RESOURCE | Load a Windows bitmap resource from the executable. |
BITMAP_TYPE_PICT_RESOURCE | Load a PICT image resource from the executable. Mac OS only. |
BITMAP_TYPE_GIF | Load a GIF bitmap file. |
BITMAP_TYPE_XBM | Load an X bitmap file. |
BITMAP_TYPE_XPM | Load an XPM bitmap file. |
The validity of these flags depends on the platform and Widgets configuration.
In addition, Bitmap can read all formats that Image can
(BITMAP_TYPE_JPEG, BITMAP_TYPE_PNG, BITMAP_TYPE_GIF, BITMAP_TYPE_PCX,
BITMAP_TYPE_PNM).
true if the operation succeeded, false otherwise.
A palette may be associated with the bitmap if one exists (especially for
colour Windows bitmaps), and if the code supports it. You can check
if one has been created by using the get_palette member.
Returns true if bitmap data is present.
Saves a bitmap in the named file.
BITMAP_TYPE_BMP | Save a Windows bitmap file. |
BITMAP_TYPE_GIF | Save a GIF bitmap file. |
BITMAP_TYPE_XBM | Save an X bitmap file. |
BITMAP_TYPE_XPM | Save an XPM bitmap file. |
The validity of these flags depends on the platform and Widgets configuration.
In addition, Bitmap can save all formats that Image can
(BITMAP_TYPE_JPEG, BITMAP_TYPE_PNG).
true if the operation succeeded, false otherwise.
Depending on how Widgets has been configured, not all formats may be available.
Sets the depth member (does not affect the bitmap data).
Sets the height member (does not affect the bitmap data).
Sets the mask for this bitmap.
The bitmap object owns the mask once this has been called.
Sets the associated palette. (Not implemented under GTK+).
Sets the width member (does not affect the bitmap data).
Assignment operator. This operator does not copy any data, but instead
passes a pointer to the data in bitmap and increments a reference
counter. It is a fast operation.
Returns ‘this’ object.
Equality operator. This operator tests whether the internal data pointers are
equal (a fast test).
Returns true if the bitmaps were effectively equal, false otherwise.
Inequality operator. This operator tests whether the internal data pointers are
unequal (a fast test).
Returns true if the bitmaps were unequal, false otherwise.
[This page automatically generated from the Textile source at 2023-06-13 21:31:32 +0000]