Cairo::PsSurface

Creates a PostScript surface of the specified size in points to be written incrementally to the stream represented by write_func and closure. See PsSurface#initialize for a more convenient way to simply direct the PostScript output to a named file.

NOTE: that the size of individual pages of the PostScript output can vary. See PsSurface#set_size.

###Parameters

• write_func a Cairo::C::LibCairo::WriteFuncT to accept the output data, may be nil to indicate a no-op write_func. With a no-op write_func, the surface may be queried or used as a source without generating any temporary files.
• closure the closure argument for write_func
• width_in_points width of the surface, in points (1 point == 1/72.0 inch)
• height_in_points height of the surface, in points (1 point == 1/72.0 inch)

###Returns A pointer to the newly created surface. The caller owns the surface and should call Surface#finalize when done with it.

This function always returns a valid pointer, but it will return a pointer to a "nil" surface if an error such as out of memory occurs. You can use Surface#status to check for this.

Creates a PostScript surface of the specified size in points to be written to filename.

NOTE: that the size of individual pages of the PostScript output can vary. See PsSurface#set_size.

###Parameters

• filename a filename for the PS output (must be writable), nil may be used to specify no output. This will generate a PS surface that may be queried and used as a source, without generating a temporary file.
• width_in_points width of the surface, in points (1 point == 1/72.0 inch)
• height_in_points height of the surface, in points (1 point == 1/72.0 inch)

###Returns A pointer to the newly created surface. The caller owns the surface and should call Surface#finalize when done with it.

This function always returns a valid pointer, but it will return a pointer to a "nil" surface if an error such as out of memory occurs. You can use Surface#status to check for this.

Used to retrieve the list of supported levels. See PsSurface#restrict_to_level.

###Returns Supported level list.

This function indicates that subsequent calls to PsSurface#dsc_comment should direct comments to the PageSetup section of the PostScript output.

This function call is only needed for the first page of a surface. It should be called after any call to PsSurface#dsc_begin_setup and before any drawing is performed to the surface.

See PsSurface#dsc_comment for more details.

This function indicates that subsequent calls to PsSurface#dsc_comment should direct comments to the Setup section of the PostScript output.

This function should be called at most once per surface, and must be called before any call to PsSurface#dsc_begin_page_setup and before any drawing is performed to the surface.

See PsSurface#dsc_comment for more details.

Emit a comment into the PostScript output for the given surface.

The comment is expected to conform to the PostScript Language Document Structuring Conventions (DSC). Please see that manual for details on the available comments and their meanings. In particular, the %%IncludeFeature comment allows a device-independent means of controlling printer device features. So the PostScript Printer Description Files Specification will also be a useful reference.

The comment string must begin with a percent character (%) and the total length of the string (including any initial percent characters) must not exceed 255 characters. Violating either of these conditions will place surface into an error state. But beyond these two conditions, this function will not enforce conformance of the comment with any particular specification.

The comment string should not have a trailing newline.

The DSC specifies different sections in which particular comments can appear. This function provides for comments to be emitted within three sections: the header, the Setup section, and the PageSetup section. Comments appearing in the first two sections apply to the entire document while comments in the BeginPageSetup section apply only to a single page.

For comments to appear in the header section, this function should be called after the surface is created, but before a call to PsSurface#dsc_begin_setup.

For comments to appear in the Setup section, this function should be called after a call to PsSurface#dsc_begin_setup but before a call to PsSurface#dsc_begin_page_setup.

For comments to appear in the PageSetup section, this function should be called after a call to PsSurface#dsc_begin_page_setup.

NOTE: that it is only necessary to call PsSurface#dsc_begin_page_setup for the first page of any surface. After a call to Context#show_page or Context#copy_page comments are unambiguously directed to the PageSetup section of the current page. But it doesn't hurt to call this function at the beginning of every page as that consistency may make the calling code simpler.

As a final note, cairo automatically generates several comments on its own. As such, applications must not manually generate any of the following comments:

Header section: %!PS-Adobe-3.0, %%Creator, %%CreationDate, %%Pages, %%BoundingBox, %%DocumentData, %%LanguageLevel, %%EndComments.

Setup section: %%BeginSetup, %%EndSetup

PageSetup section: %%BeginPageSetup, %%PageBoundingBox, %%EndPageSetup.

Other sections: %%BeginProlog, %%EndProlog, %%Page, %%Trailer, %%EOF

Here is an example sequence showing how this function might be used:

surface = PsSurface.new(filename, width, height)
...
surface.dsc_comment("%%Title: My excellent document")
surface.dsc_comment("%%Copyright: Copyright (C) 2006 Cairo Lover")
...
surface.dsc_begin_setup
surface.dsc_comment("%%IncludeFeature: *MediaColor White")
...
surface.dsc_begin_page_setup
surface.dsc_comment("%%IncludeFeature: *PageSize A3")
surface.dsc_comment("%%IncludeFeature: *InputSlot LargeCapacity")
surface.dsc_comment("%%IncludeFeature: *MediaType Glossy")
surface.dsc_comment("%%IncludeFeature: *MediaColor Blue")
... draw to first page here ..
cr.show_page
...
surface.dsc_comment("%%IncludeFeature: *PageSize A5")

###Parameters

• comment a comment string to be emitted into the PostScript output

Check whether the PostScript surface will output Encapsulated PostScript.

###Returns true if the surface will output Encapsulated PostScript.

If eps is true, the PostScript surface will output Encapsulated PostScript.

This function should only be called before any drawing operations have been performed on the current page. The simplest way to do this is to call this function immediately after creating the surface. An Encapsulated PostScript file should never contain more than one page.

###Parameters

• eps true to output EPS format PostScript.

Restricts the generated PostSript file to level. See PsSurface#levels for a list of available level values that can be used here.

This function should only be called before any drawing operations have been performed on the given surface. The simplest way to do this is to call this function immediately after creating the surface.

###Parameters

• level PostScript level

Changes the size of a PostScript surface for the current (and subsequent) pages.

This function should only be called before any drawing operations have been performed on the current page. The simplest way to do this is to call this function immediately after creating the surface or immediately after completing a page with either Context#show_page or Context#copy_page.

###Parameters

• width_in_points new surface width, in points (1 point == 1/72.0 inch)
• height_in_points new surface height, in points (1 point == 1/72.0 inch)