DeprecatedFlyString relies heavily on DeprecatedString's StringImpl, so
let's rename it to A) match the name of DeprecatedString, B) write a new
FlyString class that is tied to String.
ColorSpaces now can tell users how many components they expect, and the
default decode array that should be used when converting unit bit
sequences into color space component input values during image
rendering.
ColorSpaces can be specified in two ways: with a stream as operands of
the color space operations (CS/cs), or as a separate PDF object, which
is then referred to by other means (e.g., from Image XObjects and other
entities). These two modes of addressing a ColorSpace are slightly
different and need to be addressed separately. However, the current
implementation embedded the full logic of the first case in the routine
that created ColorSpace objects.
This commit refactors the creation of ColorSpace to support both cases.
First, a new ColorSpaceFamily class encapsulates the static aspects of a
family, like its name or whether color space construction never requires
parameters. Then we define the supported ColorSpaceFamily objects.
On top of this also sit a breakage on how ColorSpaces are created. Two
methods are now offered: one only providing construction of no-argument
color spaces (and thus taking a simple name), and another taking an
ArrayObject, hence used to create ColorSpaces requiring arguments.
Finally, on top of *that* two ways to get a color space in the Renderer
are made available: the first creates a ColorSpace with a name and a
Resources dictionary, and another takes an Object. These model the two
addressing modes described above.
Resources can come from other sources (e.g., XObjects), and since the
only attribute we are reading from Page are its resources it makes sense
to receive resources instead. That way we'll be able to pass down
arbitrary resources that are not necessarily declared at the page level.
We currently don't support ICC color spaces and fall back to a "simple"
one instead.
If no alternative is specified however, we are allowed to pick the
closest match based on the number of color components.
Old situation:
Object.h defines Object
Object.h defines ArrayObject
ArrayObject requires the definition of Object
ArrayObject requires the definition of Value
Value.h defines Value
Value requires the definition of Object
Therefore, a file with the single line "#include <Value.h>" used to
raise compilation errors; certainly not something that one might expect
from a library.
This patch splits up the definitions in Object.h to break the cycle.
Now, Object.h only defines Object, Value.h still only defines Value (and
includes Object.h), and the new header ObjectDerivatives.h defines
ArrayObject (and includes both Object.h and Value.h).
This isn't tested all that well, as the PDF I am testing with only uses
it for black (which is trivial). It can be tested further when LibPDF
is able to process more complex PDFs that actually use this color space
non-trivially.
