| Class | Fox::FXImage |
| In: |
rdoc-sources/FXImage.rb
|
| Parent: | FXDrawable |
An Image is a rectangular array of pixels. It supports two representations of these pixels: a client-side pixel buffer which is stored as an array of FXColor, and a server-side pixmap which is stored in an organization directly compatible with the screen, for fast drawing onto the device. The server-side representation is not directly accessible from the current process as it lives in the process of the X Server or GDI.
| IMAGE_KEEP: | Keep pixel data in client. By default, FOX discards of the client-side pixel data for an image after you call create() for that image. When the IMAGE_KEEP option is set for FXImage (or one of its subclasses), the client-side buffer is maintained. You will typically want to set this option if you intend to do repeated re-rendering of the image after it has been created. |
| IMAGE_OWNED: | If the IMAGE_OWNED option is set, the FXImage object assumes ownership of its client-side pixel data (if any). |
| IMAGE_DITHER: | Dither image to look better |
| IMAGE_NEAREST: | Turn off dithering and map to nearest color |
| IMAGE_OPAQUE: | Force opaque background |
| IMAGE_ALPHACOLOR: | By default, FOX will use the transparency color obtained from the image file as the transparency (alpha) color. If you pass the IMAGE_ALPHACOLOR flag, the user-specified transparency color will be used instead. |
| IMAGE_SHMI: | Using shared memory image |
| IMAGE_SHMP: | Using shared memory pixmap |
| IMAGE_ALPHAGUESS: | Guess transparency color from corners |
| data | [R] | Pixel data [FXMemoryBuffer] |
| options | [RW] | Option flags [Integer] |
Create an image. If a client-side pixel buffer has been specified, the image does not own the pixel buffer unless the IMAGE_OWNED flag is set. If the IMAGE_OWNED flag is set but a nil pixel buffer is passed, a pixel buffer will be automatically created and will be owned by the image. The flags IMAGE_SHMI and IMAGE_SHMP may be specified for large images to instruct render to use shared memory to communicate with the server.
| a: | an application instance [FXApp] |
| pixels: | pixels [Array of FXColor values] |
| opts: | image options [Integer] |
| w: | image width [Integer] |
| h: | image height [Integer] |
Crop image to given rectangle
| x: | x-coordinate for top left corner of the clip rectangle [Integer] |
| y: | y-coordinate for top left corner of the clip rectangle [Integer] |
| w: | width of the clip rectangle [Integer] |
| h: | height of the clip rectangle [Integer] |
Return the color of the pixel at (x, y).
| x: | x-coordinate of the pixel of interest [Integer] |
| y: | y-coordinate of the pixel of interest [Integer] |
Load pixel data from a stream.
Note that the base class version of loadPixels expects to read the the pixel data in a neutral format (i.e. without any image format specific information). For example, if you have a 1024x768 image without an alpha channel (and thus only the red, green and blue channels), loadPixels will attempt to read a total of 1024*768*3*8 bytes from the stream. The behavior of loadPixels is different for subclasses such as FXPNGImage, where loadPixels will instead expects to read the image data in a specific image file format (i.e. the PNG file format).
| store: | opened stream from which to read the pixel data [FXStream] |
Mirror image horizontally and/or vertically.
| horizontal: | if true, the image will be flipped from left to right [Boolean] |
| vertical: | if true, the image will be flipped from top to bottom [Boolean] |
Release the client-side pixels buffer, free it if it was owned (i.e. if the IMAGE_OWNED option is set).. If it is not owned, the image just forgets about the buffer.
Render the image from client-side pixel buffer, if there is data and if the image width and height are greater than zero.
Restore client-side pixel buffer from image. This operation overwrites any current values for the client-side pixel buffer with values corresponding to the server-side image. If the image data is nil at the time restore is called, the image will first allocate an (owned) pixel buffer to use for this operation.
Rotate image counter-clockwise by some number of degrees.
| degrees: | number of degrees by which to rotate the image [Integer] |
Save pixel data to a stream.
Note that the base class version of savePixels saves the pixel data as-is, without any image format specific information. For example, if you have a 1024x768 image without an alpha channel (and thus only the red, green and blue channels) the total number of bytes written to the stream will be 1024*768*3*8. The behavior of savePixels is different for subclasses such as FXPNGImage, where savePixels will instead save the image data in a specific image file format (i.e. the PNG file format).
| store: | opened stream to which to save the pixel data [FXStream] |
Rescale pixels image to the specified width and height. Note that this serves a slightly different purpose than the base class resize() method, which simply resizes the client-side pixel data buffer but doesn’t transform the image.
The optional third argument specifies the quality of the scaling algorithm used. By default, scale uses a fast (but low quality) nearest-neighbor algorithm for scaling the image to its new size. To use the higher-quality scaling algorithm from FOX 1.0, you should pass in a value of 1 as the third argument to scale.
| w: | new image width, in pixels [Integer] |
| h: | new image height, in pixels [Integer] |
| quality: | scaling algorithm quality, either 0 or 1 (see above) [Integer] |