allocimage(3) - Plan 9 from User Space

From adc93f6097615f16d57e8a24a256302f2144ec4e Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 14 Jan 2005 17:37:50 +0000 Subject: cut out the html - they're going to cause diffing problems. --- man/man3/allocimage.html | 321 ----------------------------------------------- 1 file changed, 321 deletions(-) delete mode 100644 man/man3/allocimage.html (limited to 'man/man3/allocimage.html') diff --git a/man/man3/allocimage.html b/man/man3/allocimage.html deleted file mode 100644 index d36fb0eb..00000000 --- a/man/man3/allocimage.html +++ /dev/null @@ -1,321 +0,0 @@ - -allocimage(3) - Plan 9 from User Space - - - - -

ALLOCIMAGE(3) ALLOCIMAGE(3) -

-
-

NAME
- -
- - allocimage, allocimagemix, freeimage, nameimage, namedimage, setalpha, - loadimage, cloadimage, unloadimage, readimage, writeimage, bytesperline, - wordsperline – allocating, freeing, reading, writing images
- -
-

SYNOPSIS
- -
- - -
- - #include <u.h> - #include <libc.h> - #include <draw.h> - - - - Image *allocimage(Display *d, Rectangle r, - - - - - - - ulong chan, int repl, int col) - - - - - - - -
- - -
- - - -
- -
- Image *allocimagemix(Display *d, ulong one, ulong three) - - - - void freeimage(Image *i) - - - - int nameimage(Image *i, char *name, int in) - - - - Image *namedimage(Display *d, char *name) - - - - ulong setalpha(ulong color, uchar alpha) - - - - int loadimage(Image *i, Rectangle r, uchar *data, int ndata) - - - - int cloadimage(Image *i, Rectangle r, uchar *data, int ndata) - - - - int unloadimage(Image *i, Rectangle r, uchar *data, int ndata) - - - - Image *readimage(Display *d, int fd, int dolock) - - - - int writeimage(int fd, Image *i, int dolock) - - - - int bytesperline(Rectangle r, int d) - - - - int wordsperline(Rectangle r, int d) - - - - enum - { - - - - DOpaque = 0xFFFFFFFF, - DTransparent = 0x00000000, - DBlack = 0x000000FF, - DWhite = 0xFFFFFFFF, - DRed = 0xFF0000FF, - DGreen = 0x00FF00FF, - DBlue = 0x0000FFFF, - DCyan = 0x00FFFFFF, - DMagenta = 0xFF00FFFF, - DYellow = 0xFFFF00FF, - DPaleyellow = 0xFFFFAAFF, - DDarkyellow = 0xEEEE9EFF, - DDarkgreen = 0x448844FF, - DPalegreen = 0xAAFFAAFF, - DMedgreen = 0x88CC88FF, - DDarkblue = 0x000055FF, - DPalebluegreen = 0xAAFFFFFF, - DPaleblue = 0x0000BBFF, - DBluegreen = 0x008888FF, - DGreygreen = 0x55AAAAFF, - DPalegreygreen = 0x9EEEEEFF, - DYellowgreen = 0x99994CFF, - DMedblue = 0x000099FF, - DGreyblue = 0x005DBBFF, - DPalegreyblue = 0x4993DDFF, - DPurpleblue = 0x8888CCFF, - DNotacolor = 0xFFFFFF00, - DNofill = DNotacolor, - - - - }; - -
-

DESCRIPTION
- -
- - A new Image on Display d is allocated with allocimage; it will - have the rectangle, pixel channel format, and replication flag - given by its arguments. Convenient pixel channels like GREY1, - GREY2, CMAP8, RGB16, RGB24, and RGBA32 are predefined. All the - new image’s pixels will have initial value col. If col - is DNofill, no initialization is done. Representative useful values - of color are predefined: DBlack, DWhite, DRed, and so on. Colors - are specified by 32-bit numbers comprising, from most to least - significant byte, 8-bit values for red, green, blue, and alpha. - The values correspond to illumination, so 0 is black - and 255 is white. Similarly, for alpha 0 is transparent and 255 - is opaque. The id field will have been set to the identifying - number used by /dev/draw (see draw(3)), and the cache field will - be zero. If repl is true, the clip rectangle is set to a very - large region; if false, it is set to r. The depth field will be - set to the - number of bits per pixel specified by the channel descriptor (see - image(7)). Allocimage returns 0 if the server has run out of image - memory. -
- - Allocimagemix is used to allocate background colors. On 8-bit - color-mapped displays, it returns a 2x2 replicated image with one - pixel colored the color one and the other three with three. (This - simulates a wider range of tones than can be represented by a - single pixel value on a color-mapped display.) On true color - displays, it returns a 1x1 replicated image whose pixel is the - result of mixing the two colors in a one to three ratio. -
- - Freeimage frees the resources used by its argument image. -
- - Nameimage publishes in the server the image i under the given - name. If in is non-zero, the image is published; otherwise i must - be already named name and it is withdrawn from publication. Namedimage - returns a reference to the image published under the given name - on Display d. These routines permit - unrelated applications sharing a display to share an image; for - example they provide the mechanism behind getwindow (see graphics(3)). - -
- - The RGB values in a color are premultiplied by the alpha value; - for example, a 50% red is 0x7F00007F not 0xFF00007F. The function - setalpha performs the alpha computation on a given color, ignoring - its initial alpha value, multiplying the components by the supplied - alpha. For example, to make a 50% red - color value, one could execute setalpha(DRed, 0x7F). -
- - The remaining functions deal with moving groups of pixel values - between image and user space or external files. There is a fixed - format for the exchange and storage of image data (see image(7)). - -
- - Unloadimage reads a rectangle of pixels from image i into data, - whose length is specified by ndata. It is an error if ndata is - too small to accommodate the pixels. -
- - Loadimage replaces the specified rectangle in image i with the - ndata bytes of data. -
- - The pixels are presented one horizontal line at a time, starting - with the top-left pixel of r. In the data processed by these routines, - each scan line starts with a new byte in the array, leaving the - last byte of the previous line partially empty, if necessary. - Pixels are packed as tightly as possible within data, regardless - of - the rectangle being extracted. Bytes are filled from most to least - significant bit order, as the x coordinate increases, aligned - so x=0 would appear as the leftmost pixel of its byte. Thus, for - depth 1, the pixel at x offset 165 within the rectangle will be - in a data byte at bit-position 0x04 regardless of the overall - rectangle: 165 mod 8 equals 5, and 0x80 >> 5 equals 0x04. -
- - Cloadimage does the same as loadimage, but for ndata bytes of - compressed image data (see image(7)). On each call to cloadimage, - the data must be at the beginning of a compressed data block, - in particular, it should start with the y coordinate and data - length for the block. -
- - Loadimage, cloadimage, and unloadimage return the number of bytes - copied. -
- - Readimage creates an image from data contained in an external - file (see image(7) for the file format); fd is a file descriptor - obtained by opening such a file for reading. The returned image - is allocated using allocimage. The dolock flag specifies whether - the Display should be synchronized for multithreaded access; - single-threaded programs can leave it zero. -
- - Writeimage writes image i onto file descriptor fd, which should - be open for writing. The format is as described for readimage. - -
- - Readimage and writeimage do not close fd. -
- - Bytesperline and wordsperline return the number of bytes or words - occupied in memory by one scan line of rectangle r in an image - with d bits per pixel.
- -
-

EXAMPLE
- -
- - To allocate a single-pixel replicated image that may be used to - paint a region red,
- -
- - red = allocimage(display, Rect(0, 0, 1, 1), RGB24, 1, DRed); - -
- -
-

SOURCE
- -
- - /usr/local/plan9/src/libdraw - -
-

SEE ALSO
- -
- - graphics(3), draw(3), draw(3), image(7)
- -
-

DIAGNOSTICS
- -
- - These functions return pointer 0 or integer –1 on failure, usually - due to insufficient memory. -
- - May set errstr.
- -
-

BUGS
- -
- - Depth must be a divisor or multiple of 8.
- -
- -

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