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# 7.3 Image Functions

The following paragraphs describe the CLX functions used to:

- Create an image object.
- Copy an image or a subimage.
- Read an image from a drawable.
- Display an image to a drawable.

create-image | &key :bit-lsb-first-p :bits-per-pixel :blue-mask :byte-lsb-first-p :bytes-per-line :data :depth :format :green-mask :height :name :plist :red-mask :width :x-hot :y-hot | Function

| :bit-lsb-first-p For a returned image, true if the order of bits in each :data byte is least-significant bit first. :bits-per-pixel One of 1, 4, 8, 16, 24, or 32. :blue-mask For :true-color or :direct-color images, a pixel mask. :byte-lsb-first-p For a returned image, true if the :data byte order is least-significant byte first. :bytes-per-line For a returned image, the number of :data bytes per scanline. :data Either a list of bitmaps, a pixarray, or an array of card8 bytes. :depth The number of bits per displayed pixel. :format One of :bitmap, :xy-format, or :z-format. :green-mask For :true-color or :direct-color images, a pixel mask. :height A card16 for the image height in pixels. :name An optional stringable for the image name. :plist An optional image property list. :red-mask For :true-color or :direct-color images, a pixel mask. :width A card16 for the image width in pixels. :x-hot For a cursor image, the x position of the hot spot. :y-hot For a cursor image, the y position of the hot spot. Creates an image object from the given :data and returns either an image, image-xy, or an image-z, depending on the type of image :data. If the :data is a list, it is assumed to be a list of bitmaps and an image-xy is created. If the :data is a pixarray, an image-z is created. Otherwise, the :data must be an array of bytes (card8), in which case a basic image object is created. If the :data is a list, each element must be a bitmap of equal size. :width and :height default to the bitmap width -- (array-dimension bitmap 1) -- and the bitmap height -- (array-dimension bitmap 0) -- respectively. :depth defaults to the number of bitmaps. If the :data is a pixarray, :width and :height default to the pixarray width -- (array-dimension pixarray 1), and the pixarray height -- (array-dimension pixarray 0), respectively. :depth defaults to (pixarray-depth :data). The :bits-per-pixel is rounded to a valid size, if necessary. By default, the :bits-per-pixel is equal to the :depth. If the :data is an array of card8, the :width and :height are required to interpret the image data correctly. The :bits-per-pixel defaults to the :depth, and the :depth defaults to 1. :bytes-per-line defaults to: (floor (length :data) (* :bits-per-pixel :height)) The :format defines the storage format of image data bytes and can be one of the following values: :xy-pixmap The :data is organized as a set of bitmaps representing image bit planes, appearing in most-significant to least-significant bit order. :z-pixmap The :data is organized as a set of pixel values in scanline order. :bitmap Similar to :xy-pixmap, except that the :depth must be 1, and 1 and 0 bits represent the foreground and background pixels, respectively. By default, the :format is :bitmap if :depth is 1; otherwise, :z-pixmap. image Type image.

copy-image | image &key (:x 0) (:y 0) :width :height :result-type | Function

| image An image object. :x, :y card16 values defining the position of the upper-left corner of the subimage copied. :width, :height card16 values defining the size of subimage copied. :result-type One of 'image-x, 'image-xy, or 'image-z. Returns a new image, of the given :result-type, containing a copy of the portion of the image defined by :x, :y, :width, and :height. By default, :width is: (- (image-width image) :x) and :height is: (- ( image-height image) :y) If necessary, the new image is converted to the :result-type , that can be one of the following values: 'image-x A basic image object is returned. 'image-xy An image-xy is returned. 'image-z An image-z is returned. new-image Type image.

get-image | drawable &key :x :y :width :height :plane-mask (:format :z-format ) :result-type | Function

| drawable A drawable. :x, :y card16 values defining the upper-left drawable pixel returned. These arguments are required. :width, :height card16 values defining the size of the image returned. These arguments are required. :plane-mask A pixel mask. :format Either :xy-pixmap or :z-pixmap. :result-type One of 'image-x, 'image-xy, or 'image-z. Returns an image containing pixel values from the region of the drawable given by :x, :y, :width , and :height. The bits for all planes selected by 1 bits in the :plane-mask are returned as zero; the default :plane-mask is all 1 bits. The :format of the returned pixel values may be either :xy-format or :z-format. The :result-type defines the type of image object returned: 'image-x A basic image object is returned. 'image-xy An image-xy is returned. 'image-z An image-z is returned. By default, :result-type is 'image-z if :format is :z-format and 'image-xy if :format is :xy-format. image Type image.

put-image | drawable gcontext image &key (:src-x 0) (:src-y 0) :x :y :width :height :bitmap-p | Function

| drawable The destination drawable. gcontext The graphics context used to display the image. image An image object. :src-x, :src-y card16 values defining the upper-left position of the image region to display. :x, :y The position in the drawable where the image region is displayed. These arguments are required. :width, :height card16 values defining the size of the image region displayed. :bitmap-p If image is depth 1, then if true, foreground and background pixels are used to display 1 and 0 bits of the image. Displays a region of the image defined by :src-x, :src-y, :width, and :height on the destination drawable, with the upper-left pixel of the image region displayed at the drawable position given by :x and :y. By default, :width is: (- (image-width image) :src-x) and :height is: (- ( image-height image) :src-y) The following attributes of the gcontext are used to display the image: clip-mask, clip-x, clip-y, function, plane-mask, and subwindow-mode. The :bitmap-p argument applies only to images of depth 1. In this case, if :bitmap-p is true or if the image is a basic image object created with :format :bitmap, the image is combined with the foreground and background pixels of the gcontext. 1 bits of the image are displayed in the foreground pixel and 0 bits are displayed in the background pixel.

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