From 530ffd0b7d3c39757b20f00716e486b5caf89aff Mon Sep 17 00:00:00 2001 From: sanine Date: Wed, 12 Oct 2022 12:03:23 -0500 Subject: add cairo --- .../doc/public/html/cairo-PNG-Support.html | 413 +++++++++++++++++++++ 1 file changed, 413 insertions(+) create mode 100644 libs/cairo-1.16.0/doc/public/html/cairo-PNG-Support.html (limited to 'libs/cairo-1.16.0/doc/public/html/cairo-PNG-Support.html') diff --git a/libs/cairo-1.16.0/doc/public/html/cairo-PNG-Support.html b/libs/cairo-1.16.0/doc/public/html/cairo-PNG-Support.html new file mode 100644 index 0000000..fd24b15 --- /dev/null +++ b/libs/cairo-1.16.0/doc/public/html/cairo-PNG-Support.html @@ -0,0 +1,413 @@ + + + + +PNG Support: Cairo: A Vector Graphics Library + + + + + + + + + + + + + + + + +
+
+
+ + +
+

PNG Support

+

PNG Support — Reading and writing PNG images

+
+
+

Functions

+
++++ + + + + + + + + + + + + + + + + + + + + + + + + + + +
+cairo_surface_t * + +cairo_image_surface_create_from_png () +
+cairo_status_t + +(*cairo_read_func_t) () +
+cairo_surface_t * + +cairo_image_surface_create_from_png_stream () +
+cairo_status_t + +cairo_surface_write_to_png () +
+cairo_status_t + +(*cairo_write_func_t) () +
+cairo_status_t + +cairo_surface_write_to_png_stream () +
+
+
+

Types and Values

+
++++ + + + + +
#defineCAIRO_HAS_PNG_FUNCTIONS
+
+
+

Description

+

The PNG functions allow reading PNG images into image surfaces, and writing +any surface to a PNG file.

+

It is a toy API. It only offers very simple support for reading and +writing PNG files, which is sufficient for testing and +demonstration purposes. Applications which need more control over +the generated PNG file should access the pixel data directly, using +cairo_image_surface_get_data() or a backend-specific access +function, and process it with another library, e.g. gdk-pixbuf or +libpng.

+
+
+

Functions

+
+

cairo_image_surface_create_from_png ()

+
cairo_surface_t *
+cairo_image_surface_create_from_png (const char *filename);
+

Creates a new image surface and initializes the contents to the +given PNG file.

+
+

Parameters

+
+++++ + + + + + +

filename

name of PNG file to load. On Windows this filename +is encoded in UTF-8.

 
+
+
+

Returns

+

a new cairo_surface_t initialized with the contents +of the PNG file, or a "nil" surface if any error occurred. A nil +surface can be checked for with cairo_surface_status(surface) which +may return one of the following values:

+

CAIRO_STATUS_NO_MEMORY +CAIRO_STATUS_FILE_NOT_FOUND +CAIRO_STATUS_READ_ERROR +CAIRO_STATUS_PNG_ERROR

+

Alternatively, you can allow errors to propagate through the drawing +operations and check the status on the context upon completion +using cairo_status().

+
+

Since: 1.0

+
+
+
+

cairo_read_func_t ()

+
cairo_status_t
+(*cairo_read_func_t) (void *closure,
+                      unsigned char *data,
+                      unsigned int length);
+

cairo_read_func_t is the type of function which is called when a +backend needs to read data from an input stream. It is passed the +closure which was specified by the user at the time the read +function was registered, the buffer to read the data into and the +length of the data in bytes. The read function should return +CAIRO_STATUS_SUCCESS if all the data was successfully read, +CAIRO_STATUS_READ_ERROR otherwise.

+
+

Parameters

+
+++++ + + + + + + + + + + + + + + + + + +

closure

the input closure

 

data

the buffer into which to read the data

 

length

the amount of data to read

 
+
+
+

Returns

+

the status code of the read operation

+
+

Since: 1.0

+
+
+
+

cairo_image_surface_create_from_png_stream ()

+
cairo_surface_t *
+cairo_image_surface_create_from_png_stream
+                               (cairo_read_func_t read_func,
+                                void *closure);
+

Creates a new image surface from PNG data read incrementally +via the read_func + function.

+
+

Parameters

+
+++++ + + + + + + + + + + + + +

read_func

function called to read the data of the file

 

closure

data to pass to read_func +.

 
+
+
+

Returns

+

a new cairo_surface_t initialized with the contents +of the PNG file or a "nil" surface if the data read is not a valid PNG image +or memory could not be allocated for the operation. A nil +surface can be checked for with cairo_surface_status(surface) which +may return one of the following values:

+

CAIRO_STATUS_NO_MEMORY +CAIRO_STATUS_READ_ERROR +CAIRO_STATUS_PNG_ERROR

+

Alternatively, you can allow errors to propagate through the drawing +operations and check the status on the context upon completion +using cairo_status().

+
+

Since: 1.0

+
+
+
+

cairo_surface_write_to_png ()

+
cairo_status_t
+cairo_surface_write_to_png (cairo_surface_t *surface,
+                            const char *filename);
+

Writes the contents of surface + to a new file filename + as a PNG +image.

+
+

Parameters

+
+++++ + + + + + + + + + + + + +

surface

a cairo_surface_t with pixel contents

 

filename

the name of a file to write to; on Windows this filename +is encoded in UTF-8.

 
+
+
+

Returns

+

CAIRO_STATUS_SUCCESS if the PNG file was written +successfully. Otherwise, CAIRO_STATUS_NO_MEMORY if memory could not +be allocated for the operation or +CAIRO_STATUS_SURFACE_TYPE_MISMATCH if the surface does not have +pixel contents, or CAIRO_STATUS_WRITE_ERROR if an I/O error occurs +while attempting to write the file, or CAIRO_STATUS_PNG_ERROR if libpng +returned an error.

+
+

Since: 1.0

+
+
+
+

cairo_write_func_t ()

+
cairo_status_t
+(*cairo_write_func_t) (void *closure,
+                       const unsigned char *data,
+                       unsigned int length);
+

cairo_write_func_t is the type of function which is called when a +backend needs to write data to an output stream. It is passed the +closure which was specified by the user at the time the write +function was registered, the data to write and the length of the +data in bytes. The write function should return +CAIRO_STATUS_SUCCESS if all the data was successfully written, +CAIRO_STATUS_WRITE_ERROR otherwise.

+
+

Parameters

+
+++++ + + + + + + + + + + + + + + + + + +

closure

the output closure

 

data

the buffer containing the data to write

 

length

the amount of data to write

 
+
+
+

Returns

+

the status code of the write operation

+
+

Since: 1.0

+
+
+
+

cairo_surface_write_to_png_stream ()

+
cairo_status_t
+cairo_surface_write_to_png_stream (cairo_surface_t *surface,
+                                   cairo_write_func_t write_func,
+                                   void *closure);
+

Writes the image surface to the write function.

+
+

Parameters

+
+++++ + + + + + + + + + + + + + + + + + +

surface

a cairo_surface_t with pixel contents

 

write_func

a cairo_write_func_t

 

closure

closure data for the write function

 
+
+
+

Returns

+

CAIRO_STATUS_SUCCESS if the PNG file was written +successfully. Otherwise, CAIRO_STATUS_NO_MEMORY is returned if +memory could not be allocated for the operation, +CAIRO_STATUS_SURFACE_TYPE_MISMATCH if the surface does not have +pixel contents, or CAIRO_STATUS_PNG_ERROR if libpng +returned an error.

+
+

Since: 1.0

+
+
+
+

Types and Values

+
+

CAIRO_HAS_PNG_FUNCTIONS

+
#define CAIRO_HAS_PNG_FUNCTIONS 1
+
+

Defined if the PNG functions are available. +This macro can be used to conditionally compile code using the cairo +PNG functions.

+

Since: 1.0

+
+
+
+

See Also

+

cairo_surface_t

+
+
+
+
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