NAME
Prima::Image - Bitmap routines
SYNOPSIS
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);
DESCRIPTION
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.
USAGE
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.
Graphic input and output
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.
File input and output
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.
Pixel formats
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.
Data access
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.
Standalone usage
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
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.
Layering
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 images on argb source surfaces can be only used with two rops, rop::Blend
(default) and rop::SrcCopy
. The former produces blending effect, while the latter copies alpha bits over to the destination surface. Also, a special rop::AlphaCopy
can be used to treat 8-bit grayscale source images as alpha maps, to replace the alpha pixels only.
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.
API
Prima::Image properties
- 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, unlesslineSize
is set together withdata
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
throughist::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 ofim::RealNumber
andim::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.
Prima::Icon properties
- 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 ofam::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 isam::MaskColor
. The transparency mask generation algorithm, turned on byam::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 inam::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 a get-call, returns all bitmap pixels, aligned to 4-byte boundary in 1-bit format. On a set-call, stores the provided transparency data with same alignment. If the SCALAR is an image object, copies its pixels as a new mask.
- maskColor COLOR
-
When
::autoMasking
set toam::MaskColor
, COLOR is used as a transparency value. - maskIndex INDEX
-
When
::autoMasking
set toam::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) orim::bpp8
(8). The latter can be used as a layered (argb) source surface to draw with blending effect.Note: if a mask with depth 8 is downgraded to depth 1, the image pixels that correspond to alpha values lesser than 255 will be reset to 0.
Prima::DeviceBitmap properties
- 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.
Prima::Image methods
- 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 eitherrop::CopyPut
orrop::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).
- extract X_OFFSET, Y_OFFSET, WIDTH, HEIGHT
-
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 ( orundef
) 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 ofrop::
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_colormask COLOR
-
Creates a new icon with bit depth 24 filled with COLOR, where the mask bits are copied from the caller image object and upgraded to bit depth 8, if needed.
- 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 aPrima::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
andscaling
options. Thezoom
default value is the one in$::application->uiScaling
, thescaling
default value isist::Quadratic
.See also: "uiScaling" in Application
Prima::Image events
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.
- HeaderReady EXTRAS
-
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
optioneventDelay
to limit the rate ofDataReady
event.
Prima::Icon methods
- 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 fromPrima::Image
except that it also rotates the mask, and ignoresfill
option - all new pixels are filled with zeros. - ui_scale %OPTIONS
-
Same as
ui_scale
fromPrima::Image
, but with few exceptions: It tries to useist::Quadratic
only when the system supports ARGB layering. Otherwise, falls back onist::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.
Prima::DeviceBitmap methods
- 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.
AUTHOR
Dmitry Karasik, <dmitry@karasik.eu.org>.