 |
|
| |
pod::Prima::Image(3) |
User Contributed Perl Documentation |
pod::Prima::Image(3) |
Prima::Image - Bitmap routines
use Prima qw(Application);
# create a new image from scratch
my $i = Prima::Image-> new(
width => 32,
height => 32,
type => im::BW, # same as im::bpp1 | im::GrayScale
);
# draw something
$i-> begin_paint;
$i-> color( cl::White);
$i-> ellipse( 5, 5, 10, 10);
$i-> end_paint;
# mangle
$i-> size( 64, 64);
# file operations
$i-> save('a.gif') or die "Error saving:$@\n";
$i-> load('a.gif') or die "Error loading:$@\n";
# draw on screen
$::application-> begin_paint;
# an image is drawn as specified by its palette
$::application-> put_image( 100, 100, $i);
# a bitmap is drawn as specified by destination device colors
$::application-> set( color => cl::Red, backColor => cl::Green);
$::application-> put_image( 200, 100, $i-> bitmap);
Prima::Image, Prima::Icon and
Prima::DeviceBitmap are classes for bitmap handling, including file
and graphic input and output. Prima::Image and
Prima::DeviceBitmap are descendants of Prima::Drawable and
represent bitmaps, stored in memory. Prima::Icon is a descendant of
Prima::Image and contains a transparency mask along with the regular
data.
Images usually are represented as a memory area, where pixel data
are stored row-wise. The Prima toolkit is no exception, however, it does not
assume that the GUI system uses the same memory format. The implicit
conversion routines are called when Prima::Image is about to be drawn
onto the screen, for example. The conversions are not always efficient,
therefore the Prima::DeviceBitmap class is introduced to represent a
bitmap, stored in the system memory in the system pixel format. These two
basic classes serve the different needs, but can be easily converted to each
other, with "image" and
"bitmap" methods. Prima::Image is a
more general bitmap representation, capable of file and graphic input and
output, plus it is supplied with number of conversion and scaling functions.
The Prima::DeviceBitmap class has almost none of additional
functionality, and is targeted to efficient graphic input and output.
Note: If you're looking for information how to display an image,
this is not the manual page. Look either at Prima::ImageViewer, or use
"put_image" /
"stretch_image" ( Prima::Drawable ) inside
your widget's onPaint.
As descendants of Prima::Drawable, all Prima::Image,
Prima::Icon and Prima::DeviceBitmap objects are subject to
three-state painting mode - normal ( disabled ), painting ( enabled ) and
informational. Prima::DeviceBitmap is, however, exists only in the
enabled state, and can not be switched to the other two.
When an object enters the enabled state, it serves as a canvas,
and all Prima::Drawable operations can be performed on it. When the
object is back to the disabled state, the graphic information is stored into
the object associated memory, in the pixel format, supported by the toolkit.
This information can be visualized by using one of
"Prima::Drawable::put_image" group
methods. If the object enters the enabled state again, the graphic
information is presented as an initial state of a bitmap.
It must be noted, that if an implicit conversion takes place after
an object enters and before it leaves the enabled state, as it is with
Prima::Image and Prima::Icon, the bitmap is converted to the
system pixel format. During such conversion some information can be lost,
due to down-sampling, and there is no way to preserve the information. This
does not happen with Prima::DeviceBitmap.
Image objects can be drawn upon images, as well as on the screen
and Prima::Widget objects. This operation is performed via one of
Prima::Drawable::put_image group methods ( see Prima::Drawable), and
can be called with the image object disregarding the paint state. The
following code illustrates the dualism of an image object, where it can
serve both as a drawing surface and as a drawing tool:
my $a = Prima::Image-> create( width => 100, height => 100, type => im::RGB);
$a-> begin_paint;
$a-> clear;
$a-> color( cl::Green);
$a-> fill_ellipse( 50, 50, 30, 30);
$a-> end_paint;
$a-> rop( rop::XorPut);
$a-> put_image( 10, 10, $a);
$::application-> begin_paint;
$::application-> put_image( 0, 0, $a);
$::application-> end_paint;
It must be noted, that
"put_image",
"stretch_image" and
"put_image_indirect" only allow
"Prima::Image" descendants to be passed as
a source image object. This functionality does not imply that the image is
internally switched to the paint-enabled state and back; on the contrary,
the painting is performed without switching and using only Prima's own code,
without using the system's graphical layer.
Another special case is a 1-bit ( monochrome ) DeviceBitmap. When
it is drawn upon a drawable with bit depth greater than 1, the drawable's
color and backColor properties are used to reflect 1 and 0 bits,
respectively. On a 1-bit drawable this does not happen, and the color
properties are not used.
Depending on the toolkit configuration, images can be read and
written in different formats. This functionality in accessible via
load() and save() methods.
Prima::image-load is dedicated to the description of loading and saving
parameters, that can be passed to the methods, so they can handle different
aspects of file format-specific options, such as multi-frame operations,
auto conversion when a format does not support a particular pixel format
etc. In this document, load() and
save() methods are illustrated only in their basic,
single-frame functionality. When called with no extra parameters, these
methods fail only if a disk I/O error occurred or an unknown image format
was used.
When an image is loaded, the old bitmap memory content is
discarded, and the image attributes are changed accordingly to the loaded
image. Along with these, an image palette is loaded, if available, and a
pixel format is assigned, closest or identical to the pixel format in the
image file.
Prima::Image supports a number of pixel formats, governed
by the "::type" property. It is reflected
by an integer value, a combination of
"im::XXX" constants. The whole set of
pixel formats is represented by colored formats, like, 16-color, 256-color
and 16M-color, and by gray-scale formats, mapped to C data types - unsigned
char, unsigned short, unsigned long, float and double. The gray-scale
formats are further subdivided to real-number formats and complex-number
format; the last ones are represented by two real values per pixel,
containing the real and the imaginary values.
Prima::Image can also be initialized from other formats,
that it does not support, but can convert data from. Currently these are
represented by a set of permutations of 32-bit RGBA format, and 24-bit BGR
format. These formats can only be used in conjunction with
"::data" property.
The conversions can be performed between any of the supported
formats ( to do so, "::type" property is
to be set-called ). An image of any of these formats can be drawn on the
screen, but if the system can not accept the pixel format ( as it is with
non-integer or complex formats ), the bitmap data are implicitly converted.
The conversion does not change the data if the image is about to be drawn;
the conversion is performed only when the image is about to be served as a
drawing surface. If, by any reason, it is desired that the pixel format is
not to be changed, the "::preserveType"
property must be set to 1. It does not prevent the conversion, but it
detects if the image was implicitly converted inside
end_paint() call, and reverts it to its previous
pixel format.
There are situations, when pixel format must be changed together
while down-sampling the image. One of four down-sampling methods can be
selected - no halftoning, 8x8 ordered halftoning, error diffusion, and error
diffusion combined with optimized palette. These can be set to the
"::conversion" property with one of
"ict::XXX" constants. When there is no
information loss, "::conversion" property
is not used.
Another special case of conversion is a conversion with a palette.
The following calls,
$image-> type( im::bpp4);
$image-> palette( $palette);
and
$image-> palette( $palette);
$image-> type( im::bpp4);
produce different results, but none of these takes into account
eventual palette remapping, because
"::palette" property does not change
bitmap pixel data, but overwrites palette information. A proper call syntax
here would be
$image-> set(
palette => $palette,
type => im::bpp4,
);
This call produces also palette pixel mapping. This syntax is most
powerful when conversion is set to those algorithms that can take in the
account the existing image pixels, to produce an optimized palette. These
are "ict::Optimized" ( by default ) and
"ict::Posterization". This syntax not only
allows remapping or downsampling to a predefined colors set, but also can be
used to limit palette size to a particular number, without knowing the
actual values of the final color palette. For example, for an 24-bit
image,
$image-> set( type => im::bpp8, palette => 32);
call would calculate colors in the image, compress them to an
optimized palette of 32 cells and finally converts to a 8-bit format.
Instead of "palette" property,
"colormap" can also be used.
The pixel values can be accessed in Prima::Drawable style,
via "::pixel" property. However,
Prima::Image introduces several helper functions on its own.
The "::data" property is used to
set or retrieve a scalar representation of bitmap data. The data are
expected to be lined up to a 'line size' margin ( 4-byte boundary ), which
is calculated as
$lineSize = int(( $image->width * ( $image-> type & im::BPP) + 31) / 32) * 4;
or returned from the read-only property
"::lineSize".
This is the line size for the data as lined up internally in
memory, however "::data" should not
necessarily should be aligned like this, and can be accompanied with a
write-only flag 'lineSize' if pixels are aligned differently:
$image-> set( width => 1, height=> 2);
$image-> type( im::RGB);
$image-> set(
data => 'RGB----RGB----',
lineSize => 7,
);
print $image-> data, "\n";
output: RGB-RGB-
Internally, Prima contains images in memory so that the first
scanline is the farthest away from the memory start; this is consistent with
general Y-axis orientation in Prima drawable terminology, but might be
inconvenient when importing data organized otherwise. Another write-only
boolean flag "reverse" can be set to 1 so
data then are treated as if the first scanline of the image is the closest
to the start of data:
$image-> set( width => 1, height=> 2, type => im::RGB);
$image-> set(
data => 'RGB-123-',
reverse => 1,
);
print $image-> data, "\n";
output: RGB-123-
Although it is possible to perform all kinds of calculations and
modification with the pixels, returned by
"::data", it is not advisable unless the
speed does not matter. Standalone PDL package with help of PDL::PrimaImage
package, and Prima-derived IPA package provide routines for data and image
analysis. Also, Prima::Image::Magick connects ImageMagick with Prima.
Prima::Image itself provides only the simplest statistic information,
namely: lowest and highest pixel values, pixel sum, sum of square pixels,
mean, variance, and standard deviation.
Some of image functionality can be used standalone, with all other
parts of the toolkit being uninitialized. The functionality is limited to
loading and saving files, and reading and writing pixels (outside
begin_paint only). All other calls are ignored. Example:
my $i = Prima::Image->new( size => [5,5]);
$i->color(cl::Red);
$i->bar(0,0,$i->size);
$i->save('1.bmp');
This feature is useful in non-interactive programs, running in
environments with no GUI access, a cgi-script with no access to X11 display,
for example. Normally, Prima fails to start in such situations, but can be
told not to initialize its GUI part by explicitly operating system-dependent
options. To do so, invoke
use Prima::noX11;
in the beginning of your program. See Prima::noX11 for more.
Generally the standalone methods support all the OS-specific
functions (i.e. color, region, etc), plus the primitives and
"put_image" methods support drawing using
Porter-Duff operators from "rop" property
(i e rop::SrcOver and above).
See individual methods and properties in API that support
standalone usage, and how they differ from system-dependent
implementation.
Prima::Icon inherits all properties of Prima::Image,
and it also provides a transparency mask of either 1 or 8 bits. This mask
can also be loaded and saved into image files, if the format supports
transparency information.
Similar to Prima::Image::data property,
Prima::Icon::mask property provides access to the binary mask data.
The mask can be updated automatically, after an icon object was subject to
painting, resizing, or other destructive change. The auxiliary properties
"::autoMasking" and
"::maskColor"/"::maskIndex"
regulate mask update procedure. For example, if an icon was loaded with the
color ( vs. bitmap ) transparency information, the binary mask will be
generated anyway, but it will be also recorded that a particular color
serves as a transparent indicator, so eventual conversions can rely on the
color value, instead of the mask bitmap.
If an icon is drawn upon a graphic canvas, the image output is
constrained to the mask. On raster displays it is typically simulated by a
combination of and- and xor- operation modes, therefore attempts to put an
icon with "::rop", different from
"rop::CopyPut", usually fail.
The term layered window is borrowed from Windows world, and
means a window with transparency. In Prima, the property layered is used to
select this functionality. The call to
"$::application->get_system_value(sv::LayeredWidgets)"
can check whether this functionality is available; if not, the property is
ignored. By default, widgets can not use layering.
A layered drawable uses an extra alpha channel to designate the
transparency. Drawing on widgets will also look different - for example,
drawing with black color will make the black pixels fully transparent, while
other colors will blend with the underlying background, but never in full.
Prima provides graphics primitives to draw using alpha effects, and some
image functions to address the alpha surfaces.
"put_image" /
"stretch_image" functions can operate on
surfaces with alpha as source and destination drawables. To address the
alpha channel on a drawable with Prima, one has to send either an
"Prima::Icon" with
maskType(im::bpp8), or a layered
"DeviceBitmap" to these functions.
The corresponding
"Prima::DeviceBitmap" type is
"dbt::Layered", and is fully compatible
with layered widgets in the same fashion as
"DeviceBitmap" with type
"dbt::Pixmap" is fully compatible with
normal widgets. One of ways to put a constant alpha value over a rectangle
is this, for example:
my $a = Prima::Icon->new(
width => 1,
height => 1,
type => im::RGB,
maskType => im::bpp8,
data => "\0\0\0",
mask => chr( $constant_alpha ),
);
$drawable-> stretch_image( 0, 0, 100, 100, $a, rop::SrcOver );
If displaying a picture with pre-existing alpha channel, you'll
need to call premultiply_alpha, because picture renderer assumes that pixel
values are premultiplied.
Even though addressing alpha values of pixels when drawing on
layered surfaces is not straightforward, the conversion between images and
device bitmaps fully supports alpha pixels. This means that:
* When drawing on an icon with 8-bit alpha channel (argb
icon), any changes to alpha values of pixels will be transferred back to the
mask property after "end_paint"
* Calls to "icon" function on
DeviceBitmap with type "dbt::Layered"
produce identical argb icons. Calls to
"bitmap" on argb icons produce identical
layered device bitmaps.
* Putting argb icons and layered device bitmap on other drawables
yields identical results.
Putting of argb source surfaces can be only used with two rops,
"rop::SrcOver" (default) and
"rop::SrcCopy". The former produces
blending effect, while the latter copies alpha bits over to the destination
surface. Prima internal implementation of
"put_image" and
"stretch_image" functions extends the
allowed set of rops when operating on images outside the
begin_paint/end_paint brackets. These rops support 12 Porter-Duff operators,
some more "photoshop" operators, and special flags to specify
constant alpha values to override the existing alpha channel, if any. See
more in "Raster operations" in Prima::Drawable.
Caveats: In Windows, mouse events will not be delivered to the
layered widget if the pixel under the mouse pointer is fully
transparent.
See also: examples/layered.pl.
- colormap
@PALETTE
- A color palette, used for representing 1, 4, and 8-bit bitmaps, when an
image object is to be visualized. @PALETTE
contains individual colors component triplets, in RGB format. For example,
black-and-white monochrome image may contain colormap as
"0,0xffffff".
See also "palette".
- conversion
TYPE
- Selects the type of dithering algorithm to be used for pixel
down-sampling. TYPE is one of "ict::XXX"
constants:
ict::None - no dithering, with static palette or palette optimized by source palette
ict::Posterization - no dithering, with optimized palette by source pixels
ict::Ordered - fast 8x8 ordered halftone dithering with static palette
ict::ErrorDiffusion - error diffusion dithering with static palette
ict::Optimized - error diffusion dithering with optimized palette
As an example, if a 4x4 color image with every pixel set to
RGB(32,32,32), converted to a 1-bit image, the following results
occur:
ict::None, ict::Posterization:
[ 0 0 0 0 ]
[ 0 0 0 0 ]
[ 0 0 0 0 ]
[ 0 0 0 0 ]
ict::Ordered:
[ 0 0 0 0 ]
[ 0 0 1 0 ]
[ 0 0 0 0 ]
[ 1 0 0 0 ]
ict::ErrorDiffusion, ict::Ordered:
[ 0 0 1 0 ]
[ 0 0 0 1 ]
[ 0 0 0 0 ]
[ 0 0 0 0 ]
Values of these constants are made from "ictp::" in
Prima::Const and "ictd::" in Prima::Const constants.
- data SCALAR
- Provides access to the bitmap data. On get-call, returns all bitmap
pixels, aligned to 4-byte boundary. On set-call, stores the provided data
with same alignment. The alignment can be altered by submitting 'lineSize'
write-only flag to set call; the ordering of scan lines can be altered by
setting 'reverse' write-only flag ( see "Data access" ).
- height INTEGER
- Manages the vertical dimension of the image data. On set-call, the image
data are changed accordingly to the new height, and depending on
"::vScaling" property, the pixel values
are either scaled or truncated.
- lineSize
INTEGER
- A read-only property, returning the length of an image row in bytes, as
represented internally in memory. Data returned by
"::data" property are aligned with
"::lineSize" bytes per row, and setting
"::data" expects data aligned with this
value, unless "lineSize" is set together
with "data" to indicate another
alignment. See "Data access" for more.
- mean
- Returns mean value of pixels. Mean value is
"::sum" of pixel values, divided by
number of pixels.
- palette [ @PALETTE
]
- A color palette, used for representing 1, 4, and 8-bit bitmaps, when an
image object is to be visualized. @PALETTE
contains individual color component triplets, in BGR format. For example,
black-and-white monochrome image may contain palette as
"[0,0,0,255,255,255]".
See also "colormap".
- pixel ( X_OFFSET, Y_OFFSET )
PIXEL
- Provides per-pixel access to the image data when image object is in
disabled paint state.
Pixel values for grayscale 1- and 4- bit images are treated
specifically, such that like 8-bit function, values cover range between
0 and 255. F.ex. pixel values for grayscale 1 bit images are 0 and 255,
not 0 and 1.
In paint state same as
"Prima::Drawable::pixel".
- preserveType
BOOLEAN
- If 1, reverts the image type to its old value if an implicit conversion
was called during end_paint().
- rangeHi
- Returns maximum pixel value in the image data.
- rangeLo
- Returns minimum pixel value in the image data.
- scaling INT
- Declares the scaling strategy when image is resized. Strategies
"ist::None" through
"ist::Box" are very fast scalers, others
not so.
Can be one of "ist:::XXX"
constants:
ist::None - image will be either stripped (when downsizing)
or padded (when upsizing) with zeros
ist::Box - image will be scaled using simple box transform
ist::BoxX - columns will behave same as in ist::None,
rows will behave same as in ist::Box
ist::BoxY - rows will behave same as in ist::None,
columns will behave same as in ist::Box
ist::AND - when row or columns is to be shrunk, leftover pixels
will be AND-end together (for black on white)
( does not work for floating point pixels )
ist::OR - when row or columns is to be shrunk, leftover pixels
will be OR-end together (for white on black)
( does not work for floating point pixels )
ist::Triangle - bilinear interpolation
ist::Quadratic - 2rd order (quadratic) B-Spline approximation of Gaussian
ist::Sinc - sine function
ist::Hermite - B-Spline interpolation
ist::Cubic - 3rd order (cubic) B-Spline approximation of Gaussian
ist::Gaussian - Gaussian transform with gamma=0.5
Note: Resampling scaling algorithms (those greater than
"ist::Box"), when applied to Icons
with 1-bit icon mask, will silently convert the mask in 8-bit and apply
the same scaling algorithm to it. This will have great smoothing effect
on mask edges if the system supports ARGB layering (see
"Layering" ).
- size WIDTH, HEIGHT
- Manages dimensions of the image. On set-call, the image data are changed
accordingly to the new dimensions, and depending on
"::scaling" property, the pixel values
are either scaled or truncated.
- stats ( INDEX )
VALUE
- Returns one of calculated values, that correspond to INDEX, which is one
of the following "is::XXX" constants:
is::RangeLo - minimum pixel value
is::RangeHi - maximum pixel value
is::Mean - mean value
is::Variance - variance
is::StdDev - standard deviation
is::Sum - sum of pixel values
is::Sum2 - sum of squares of pixel values
The values are re-calculated on request and cached. On
set-call VALUE is stored in the cache, and is returned on next get-call.
The cached values are discarded every time the image data changes.
These values are also accessible via set of alias properties:
"::rangeLo",
"::rangeHi",
"::mean",
"::variance",
"::stdDev",
"::sum",
"::sum2".
- stdDev
- Returns standard deviation of the image data. Standard deviation is the
square root of "::variance".
- sum
- Returns sum of pixel values of the image data
- sum2
- Returns sum of squares of pixel values of the image data
- type TYPE
- Governs the image pixel format type. TYPE is a combination of
"im::XXX" constants. The constants are
collected in groups:
Bit-depth constants provide size of pixel is bits. Their
actual value is same as number of bits, so
"im::bpp1" value is 1,
"im::bpp4" - 4, etc. The valid
constants represent bit depths from 1 to 128:
im::bpp1
im::bpp4
im::bpp8
im::bpp16
im::bpp24
im::bpp32
im::bpp64
im::bpp128
The following values designate the pixel format category:
im::Color
im::GrayScale
im::RealNumber
im::ComplexNumber
im::TrigComplexNumber
im::SignedInt
Value of "im::Color" is 0,
whereas other category constants represented by unique bit value, so
combination of "im::RealNumber" and
"im::ComplexNumber" is possible.
There also several mnemonic constants defined:
im::Mono - im::bpp1
im::BW - im::bpp1 | im::GrayScale
im::16 - im::bpp4
im::Nibble - im::bpp4
im::256 - im::bpp8
im::RGB - im::bpp24
im::Triple - im::bpp24
im::Byte - gray 8-bit unsigned integer
im::Short - gray 16-bit unsigned integer
im::Long - gray 32-bit unsigned integer
im::Float - float
im::Double - double
im::Complex - dual float
im::DComplex - dual double
im::TrigComplex - dual float
im::TrigDComplex - dual double
Bit depths of float- and double- derived pixel formats depend
on a platform.
The groups can be masked out with the mask values:
im::BPP - bit depth constants
im::Category - category constants
im::FMT - extra format constants
The extra formats are the pixel formats, not supported by
"::type", but recognized within the
combined set-call, like
$image-> set(
type => im::fmtBGRI,
data => 'BGR-BGR-',
);
The data, supplied with the extra image format specification
will be converted to the closest supported format. Currently, the
following extra pixel formats are recognized:
im::fmtBGR
im::fmtRGBI
im::fmtIRGB
im::fmtBGRI
im::fmtIBGR
- variance
- Returns variance of pixel values of the image data. Variance is
"::sum2", divided by number of pixels
minus square of "::sum" of pixel
values.
- width INTEGER
- Manages the horizontal dimension of the image data. On set-call, the image
data are changed accordingly to the new width, and depending on
"::scaling" property, the pixel values
are either scaled or truncated.
- autoMasking
TYPE
- Selects whether the mask information should be updated automatically with
"::data" change or not. Every
"::data" change is mirrored in
"::mask", using TYPE, one of
"am::XXX" constants:
am::None - no mask update performed
am::MaskColor - mask update based on ::maskColor property
am::MaskIndex - mask update based on ::maskIndex property
am::Auto - mask update based on corner pixel values
The "::maskColor" color
value is used as a transparent color if TYPE is
"am::MaskColor". The transparency mask
generation algorithm, turned on by
"am::Auto" checks corner pixel values,
assuming that majority of the corner pixels represents a transparent
color. Once such color is found, the mask is generated as in
"am::MaskColor" case.
"::maskIndex" is the same as
"::maskColor", except that it points
to a specific color index in the palette.
When image "::data" is
stretched, "::mask" is stretched
accordingly, disregarding the
"::autoMasking" value.
- mask SCALAR
- Provides access to the transparency bitmap. On get-call, returns all
bitmap pixels, aligned to 4-byte boundary in 1-bit format. On set-call,
stores the provided transparency data with same alignment.
- maskColor
COLOR
- When "::autoMasking" set to
"am::MaskColor", COLOR is used as a
transparency value.
- maskIndex
INDEX
- When "::autoMasking" set to
"am::MaskIndex", INDEXth color in the
current palette is used as a transparency value.
- maskLineSize
INTEGER
- A read-only property, returning the length of mask row in bytes, as
represented internally in memory. Data returned by
"::mask" property are aligned with
"::maskLineSize" bytes per row.
- maskType
INTEGER
- Is either "im::bpp1" (1) or
"im::bpp8" (8). The latter can be used
as a layered (argb) source surface to draw with blending effect.
- type INTEGER
- A read-only property, that can only be set during creation, reflects
whether the system bitmap is black-and-white 1-bit
("dbt::Bitmap"), is colored and
compatible with widgets ("dbt::Pixmap"),
or is colored with alpha channel and compatible with layered widgets
("dbt::Layered").
The color depth of a bitmap can be read via
get_bpp() method; monochrome bitmaps always have
bit depth of 1, layered bitmaps have bit depth of 32.
- bar X1, Y1, X2, Y2
- Outside the paint state uses own implementation for drawing a rectangular
shape. The following properties are respected:
"color",
"backColor",
"rop",
"rop2",
"fillPattern",
"fillPatternOffset",
"region".
"rop2" accepts either
"rop::CopyPut" or
"rop::NoOper" values, to produce either
opaque or transparent fill pattern application.
Inside the paint state is identical to
"Drawable::bar".
- bitmap
- Returns newly created Prima::DeviceBitmap instance, with the image
dimensions and with the bitmap pixel values copied to.
- clear [X1, Y1, X2,
Y2]
- Same as "Drawable::clear" but can be
used also outside of the paint state.
- clone %properties
- Creates a copy of the image and applies
%properties. An easy way to create a down-sampled
copy, for example.
- codecs
- Returns array of hashes, each describing the supported image format. If
the array is empty, the toolkit was set up so it can not load and save
images.
See Prima::image-load for details.
This method can be called without object instance:
perl -MData::Dumper=Dumper -MPrima::noX11 -MPrima -le 'print Dumper(Prima::Image->codecs)'
- dup
- Returns a duplicate of the object, a newly created Prima::Image,
with all information copied to it. Does not preserve graphical properties
(color etc).
- Returns a newly created image object with WIDTH and HEIGHT dimensions,
initialized with pixel data from X_OFFSET and Y_OFFSET in the bitmap.
- fill_chord,
fill_ellipse, fill_sector, flood_fill
- Same as "Drawable::" functions but can
be used also outside of the paint state.
- get_bpp
- Returns the bit depth of the pixel format. Same as
"::type & im::BPP".
- get_handle
- Returns a system handle for an image object.
- load (FILENAME or FILEGLOB) [
%PARAMETERS ]
- Loads image from file FILENAME or stream FILEGLOB into an object, and
returns the success flag. The semantics of load()
is extensive, and can be influenced by PARAMETERS hash.
load() can be called either in a context of an
existing object, then a boolean success flag is returned, or in a class
context, then a newly created object ( or
"undef" ) is returned. If an error
occurs, $@ variable contains the error description
string. These two invocation semantics are equivalent:
my $x = Prima::Image-> create();
die "$@" unless $x-> load( ... );
and
my $x = Prima::Image-> load( ... );
die "$@" unless $x;
See Prima::image-load for details.
NB! When loading from streams on win32, mind
"binmode".
- load_stream
BASE64_STRING, %OPTIONS
- Decodes BASE64_STRING and tries to load an image from it. Returns image
reference(s) on success, or "undef" on
failure; also $@ is set in this case.
- map COLOR
- Performs iterative mapping of bitmap pixels, setting every pixel to
"::color" property with respect to
"::rop" type if a pixel equals to COLOR,
and to "::backColor" property with
respect to "::rop2" type otherwise.
"rop::NoOper" type can be
used for color masking.
Examples:
width => 4, height => 1, data => [ 1, 2, 3, 4]
color => 10, backColor => 20, rop => rop::CopyPut
rop2 => rop::CopyPut
input: map(2) output: [ 20, 10, 20, 20 ]
rop2 => rop::NoOper
input: map(2) output: [ 1, 10, 3, 4 ]
- mirror VERTICAL
- Mirrors the image depending on boolean flag VERTICAL
- premultiply_alpha
CONSTANT_OR_IMAGE
- Applies premultiplication formula to each pixel
pixel = pixel * alpha / 256
where alpha either is a constant, or a pixel value in an
image
- put_image,
put_image_indirect, stretch_image
- Same as "Drawable::" functions but can
be used also outside of the paint state.
Extends raster functionality to access alpha channel either
using constant alpha values or
"Prima::Icon" as sources. See
explanation of "rop::" constants in
"Raster operations" in Prima::Drawable.
- resample SRC_LOW,
SRC_HIGH, DEST_LOW, DEST_HIGH
- Performs linear scaling of gray pixel values from range (SRC_LOW -
SRC_HIGH) to range (DEST_LOW - DEST_HIGH). Can be used to visualize gray
non-8 bit pixel values, by the code:
$image-> resample( $image-> rangeLo, $image-> rangeHi, 0, 255);
- rotate DEGREES
[,FILL_COLOR]
- Rotates the image. Where the angle is 90, 180, or 270 degrees, fast pixel
flipping is used, otherwise fast Paeth rotation is used. Eventual
resampling can be controlled by
"scaling" property ( probably not worth
it for functions with support of more than 1 pixel).
Fills empty pixels with optional fill color.
Resulting images can be 1 pixel too wide due to horizontal
shearing applied twice, where in worst cases 1 pixel from the original
image can take 3 horizontal pixels on the result.
- save (FILENAME or FILEGLOB), [
%PARAMETERS ]
- Stores image data into image file FILENAME or stream FILEGLOB, and returns
the success flag. The semantics of save() is
extensive, and can be influenced by PARAMETERS hash. If error occurs,
$@ variable contains error description string.
Note that when saving to a stream,
"codecID" must be explicitly given in
%PARAMETERS.
See Prima::image-load for details.
NB! When saving to streams on win32, mind
"binmode".
- save_stream
BASE64_STRING, %OPTIONS
- Saves image into a datastream and return it encoded in base64. Unless
$OPTIONS{codecID} or
"$image-"{extras}->{codecID}> is
set, tries to find the best codec for the job.
Returns encoded content on success, or
"undef" on failure;
$@ is set in the latter case.
- scanline Y
- Returns a scanline from Y in the same raw format as
"data"
- shear X, Y
- Applies shearing to the image. If the shearing is needed only for one
axis, set shear factor for the other one to zero.
- convert_to_icon
$MASK_DEPTH, $MASK_TEMPLATE
- Creates an icon from image, with $MASK_DEPTH
integer (can be either 1 or 8), and
$$MASK_TEMPLATE scalar used for newly populate
mask.
- to_rgba
TYPE=undef
- Creates a new icon with type set to 24 or 8 gray bits and mask type to 8
bit. If TYPE is set, uses this type instead.
- to_region
- Creates a new Prima::Region object with the image as the data source.
- transform matrix
=> [a,b,c,d,x,y], [ fill => color ]
- Applies generic 2D transform matrix to the image, fills empty pixels with
optional fill color.
Required option "matrix"
should point to an array of 6 float numbers, where these represent a
standard 3x2 matrix for 2D transformation, f ex a
"Prima::matrix" object.
Tries first to split matrix into series of shear and scale
transforms using LDU decomposition; if an interim image is calculated to
be too large, fails and returns
"false".
The last two members (X and Y translation) only use mantissa
and ignore the rest, so setting them f ex to 10.5 will not produce an
image 11 pixels larger, but only 1. The translation is thus effectively
sub-pixel.
Rotation matrices can be applied too, however, when angles are
close to 90 and 270, either interim images become too big, or defects
introduced by shearing become too visible. Therefore the method
specifically detects for rotation cases, and uses Paeth rotation
algorithm instead, which yields better results. Also, if the angle is
detected to be 90, 180, or 270 degrees, fast pixel flipping is used.
Eventual resampling can be controlled by
"scaling" property.
- ui_scale
%OPTIONS
- Resizes the image with smooth scaling. Understands
"zoom" and
"scaling" options. The
"zoom" default value is the one in
"$::application->uiScaling", the
"scaling" default value is
"ist::Quadratic" .
See also: "uiScaling" in Application
"Prima::Image"-specific events
occur only from inside load call, to report image loading progress. Not all
codecs (currently JPEG,PNG,TIFF only) are able to report the progress to the
caller. See "Loading with progress indicator" in Prima::image-load
for details, "watch_load_progress" in Prima::ImageViewer and
"load" in Prima::Dialog::ImageDialog for suggested use.
- Called whenever image header is read, and image dimensions and pixel type
is changed accordingly to accommodate image data.
"EXTRAS" is the hash to be
stored later in "{extras}" key on the
object.
- DataReady X, Y,
WIDTH, HEIGHT
- Called whenever image data that cover area designated by X,Y,WIDTH,HEIGHT
is acquired. Use "load" option
"eventDelay" to limit the rate of
"DataReady" event.
- alpha ALPHA <X1, Y1, X2,
Y2>
- Same as "Drawable::alpha" but can be
used also outside of the paint state.
- combine DATA,
MASK
- Copies information from DATA and MASK images into
"::data" and
"::mask" property. DATA and MASK are
expected to be images of same dimension.
- create_combined
DATA, MASK, %SET
- Same as "combine", but to be called as
constructor, and sets properties in %SET
- image %opt
- Renders icon graphics on a newly created Prima::Image object
instance upon black background. If
$opt{background} is given, it is used
instead.
- maskline Y
- Returns a mask scanline from Y in the same raw format as
"mask"
- premultiply_alpha
CONSTANT_OR_IMAGE = undef
- Applies premultiplication formula to each pixel
pixel = pixel * alpha / 255
where alpha is the corresponding alpha value for each
coordinate. Only applicable when
"maskType" is <im::bpp8>.
- rotate,
transform
- Applies same transformation as in
"Prima::Image" to both color and mask
pixels. Ignores fill color, fills with zeros both planes.
- split
- Returns two new Prima::Image objects of same dimension. Pixels in
the first is are duplicated from
"::data" storage, in the second - from
"::mask" storage.
- translate matrix
=> [a,b,c,d,x,y]
- Same as the "translate" method from
"Prima::Image" except that it also
rotates the mask, and ignores "fill"
option - all new pixels are filled with zeros.
- ui_scale
%OPTIONS
- Same as "ui_scale" from
"Prima::Image", but with few exceptions:
It tries to use "ist::Quadratic" only
when the system supports ARGB layering. Otherwise, falls back on
"ist::Box" scaling algorithm, and also
limits the zoom factor to integers (2x, 3x etc) only, because when
displayed, the smooth-scaled color plane will not match mask plane
downgraded to 0/1 mask, and because box-scaling with non-integer zooms
looks ugly.
- dup
- Returns a duplicate of the object, a newly created
Prima::DeviceBitmap, with all information copied to it. Does not
preserve graphical properties (color etc).
- icon
- Returns a newly created Prima::Icon object instance, with the pixel
information copied from the object. If the bitmap is layered, returns
icons with maskType set to
"im::bpp8".
- image
- Returns a newly created Prima::Image object instance, with the
pixel information copied from the object.
- get_handle
- Returns a system handle for a system bitmap object.
Dmitry Karasik, <dmitry@karasik.eu.org>.
Prima, Prima::Drawable, Prima::image-load, Prima::codecs.
PDL, PDL::PrimaImage, IPA
ImageMagick, Prima::Image::Magick
Visit the GSP FreeBSD Man Page Interface. Output converted with ManDoc.
|