Graphics2D(3pm)

💖 NAME 💖

PDL::Graphics2D — an object oriented interface to PDL graphics ✨

(hey bestie, you're reading Graphics2D(3pm) from the User Contributed Perl Documentation, and honestly? it's a whole vibe.)

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🎀 SYNOPSIS 🎀

use PDL::Graphics2D;
$win = PDL::Graphics2D->new(<Interface>, <Options>);

$w = imag2d( $image, 'Title Here', ... );

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🦋 DESCRIPTION 🦋

okay so PDL::Graphics2D is giving umbrella class energy — it's the one simple interface that lets you reach all the plotting routines in PDL. that's the whole point of it.

and no cap: on its own it does literally no work. it just passes your info along to whatever class actually knows what to do with it. ideally it should probably offer a uniform interface to a variety of packages — that's the dream 💭.

ngl, this needs a lot more work before it's truly useful (that's the original authors' own read, not mine), but fr fr it can be used already. 💅

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🌈 CONSTRUCTORS 🌈

⭐ new ⭐

Create a 2-D graphics object with the requested interface type. slay, that's it, that's the constructor.

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🔥 FUNCTIONS 🔥

📸 imag2d 📸

Display a 2-D image in a figure window. main character behavior honestly.

imag2d() creates a plain FreeGLUT OpenGL window and displays the input image with a 1:1 aspect ratio for pixels. the window resize is constrained to the actual ratio of the image dimensions — so it never gets squished, we love that. the initial display size is currently a 200x200 window, which exists to prevent things from being too small by default 🙈.

the image you pass in can have dimensions ($c,$M,$N), and here's the mapping bestie, memorize it:

• for $c==4 → the display is GL_RGBA
• for $c==3 → the display is GL_RGB
• for $c==2 → the display is GL_LUMINANCE_ALPHA
• for $c==1, or for dimensions ($M,$N) → the display is GL_LUMINANCE

this routine does not yet broadcast, but multiple images may be viewed at the same time in separate windows by multiple calls to imag2d(). TriD graphics visualization windows and the imag2d() windows may be created and used independently. 🫶

⚠️ NOTE: if you are twiddling a TriD window, the imag2d() windows are active as well. but if you call twiddle() the sub, only the imag2d() windows will update correctly. iykyk 💀

$window_id = imag2d($image, $name, $zoom, $x_off, $y_off);

• creates a new image figure window from the input ndarray with the given title, zoom factor, and position (if possible)
• $window_id — may be used to refer to the figure window
• $image — 2D image ndarray with at least 2 or 3 dimensions, e.g. [M,N], [1,M,N], [2,M,N], [3,M,N], [4,M,N]
• $name — the name to use for the figure window (optional)
• $zoom — desired (float) pixel zoom factor (optional)
• ($x_off, $y_off) — desired window pixel position (optional), with (0,0) as the top left pixel of the display

and here's the little demo, go off 🎀:

use PDL::Graphics2D;     # imports imag2d() and twiddle()

$x = sequence(64,48,3);  # make test RGB image
$x = $x->mv(2,0);        # color must be dim(0) with size [0..4]
$x /= $x->max;           # pixel values in [0.0,1.0]
$x = sin(10*$x);
$w1 = imag2d($x);        # with parens...
$w2 = imag2d $x->sqrt;   # or without
$w3 = imag2d $x**2;

🔄 imag2d_update 🔄

Update an existing imag2d window with new ndarray data. glow-up, but for pixels ✨

$image = random(3,64,48)/2 + 0.25;  # random pixel image
$win = imag2d($image);              # create original image display

imag2d_update($win, $image->sequence/$image->nelem);  # update data

imag2d_update allows one to update an imag2d display window by replacing the associated image data with new contents. the new image data must be the same type and shape as the previous — no switching up the shape mid-update bestie, it will not go well.

eventually, the dream is to implement this via some sort of dataflow that would be transparent to the user. someday 🌸

🌀 twiddle 🌀

Enable GUI interaction with a FreeGLUT display window. with an argument, it sets the default value for the auto-twiddling state. 0 will disable the automatic twiddling, and 1, or true, will enable twiddling.

twiddle();     # same as twiddle(undef)

  Runs the FreeGLUT event loop so window GUI operations
  such as resize, expose, mouse click,.. work

twiddle(0);  # disables twiddle looping for next twiddle() call
twiddle(1);  # re-enables default twiddle looping for next twiddle() call

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okay that's the whole page bestie, you ate that 💅✨ this was perl v5.38.2, dated 2024-04-10, and yes the page is Graphics2D(3pm) — go make some iconic plots, mwah 🫶💖