Why are pictures always rectangular?

I find it wierd that picture are always rectangular... Always. I know I can make an image look a different shape by making it have a transparent background, or colouring its background the same colour as the web page I would be using it on. But I have yet to see a picture-editing program that allows me to change the shape, of the box that the blank picture is in.
Or when I change the resolution of one side of the picture, it changes the other side as well, what the hell?

Who decided that those are the rules? That all pictures are square unless a transparent background is used and that when you change the resolution of one side of the rectangular picture, it changes the size of the other side as well.



Why are we restricted?
Loadsgood.

Historically, digital images have been stored as 2 dimesional arrays of integers.

Look at the standard resolutions of computer monitors:

640x480
800x600
1024x768
etc.

None of them are square.  They are all rectangular, so, graphics programs are designed to fit the monitor.

well if you wanted an oval drawing space; either the oval would be jagged, or it would need alpha blending to look smooth. this is because the screen uses square pixels. a jagged oval is not worth much, and if you want alpha blending it needs to be done within a rectangle anyway, in order to shape the outer rim of the oval. if display technology in the future works in a way in which square pixels aren't used then maybe you can talk about different shaped drawing spaces but not before then.

btw if you look at art before computers a lot of canvases have been oval, but still they would have been cut from a rectangle shape. because its easier and more efficient to produce canvas in rectangle shapes and allows the buyer to cut it anyway he wants, while with an oval he would be limited.

Loadsgood wrote:

I find it wierd that picture are always rectangular... Always. I know I can make an image look a different shape by making it have a transparent background, or colouring its background the same colour as the web page I would be using it on. But I have yet to see a picture-editing program that allows me to change the shape, of the box that the blank picture is in.
Or when I change the resolution of one side of the picture, it changes the other side as well, what the hell?

Who decided that those are the rules? That all pictures are square unless a transparent background is used and that when you change the resolution of one side of the rectangular picture, it changes the size of the other side as well.



Why are we restricted?
Loadsgood.

God, quite literally. The retina has what could be equated to hardware image pre-processors. One of them serves to identify horizontal and vertical lines.  Thus it takes less ‘thinking power’ recognized something that has a horizontal and vertical line in it. 

Close... actually the ease of recognizing horizontal and vertical lines applies much more to computers than it does to humans.

In particular, given:

Window A of width w_a and height h_a at (x_a, y_a)
Window B of width w_b and height h_b at (x_b, y_b)

it is easy to calculate the region of overlap - which is also a rectangle!

This isn't the case with any other shape.

A nice "why are manhole covers round" question

Seems technology isn't up to the height of my needs yet again Maybe one day 3D monitors or holograms/3D projections etc. will be created and my dream for the creation of non-rectangular pictures will come true Or I could just wack Paint.NET's source code into a triangular blank picture creator or a pentagon or hexagon etc. Maybe even go one step further and make circular shapes or enable the user to reshape the rectangular blank picture via clicking and dragging tiny boxes attached to the lines.... Hmmmm.



A square is a type of rectangle. By definition a rectangle is a rectangle if it has two pairs of sides that are the same length as the opposite side, a square qualifies.
Loadsgood.

Loadsgood wrote:

Seems technology isn't up to the height of my needs yet again Maybe one day 3D monitors or holograms/3D projections etc. will be created and my dream for the creation of non-rectangular pictures will come true Or I could just wack Paint.NET's source code into a triangular blank picture creator or a pentagon or hexagon etc. Maybe even go one step further and make circular shapes or enable the user to reshape the rectangular blank picture via clicking and dragging tiny boxes attached to the lines.... Hmmmm.



A square is a type of rectangle. By definition a rectangle is a rectangle if it has two pairs of sides that are the same length as the opposite side, a square qualifies.
Loadsgood.

I once seriously tried hex pixel emulation in Paint. Believe me when I say it's not worth it.

Loadsgood wrote:

A square is a type of rectangle. By definition a rectangle is a rectangle if it has two pairs of sides that are the same length as the opposite side, a square qualifies.

Almost that's a parallelogram.

A rectangle is a parallelogram whose angles are all equal.

A rhombus (AKA diamond) is a parallelogram whose sides are all equal.

A square is a rectangle that is also a rhombus.

Maurits wrote:

Almost that's a parallelogram.

A rectangle is a parallelogram whose angles are all equal.

A rhombus (AKA diamond) is a parallelogram whose sides are all equal.

A square is a rectangle that is also a rhombus.

Wouldn't "quadrilateral" be more appropriate?

Maurits wrote:

A nice "why are manhole covers round" question

Where I live, manhole covers are rectangles.

W3bbo wrote:

Maurits wrote:A nice "why are manhole covers round" question

Where I live, manhole covers are rectangles.

Look out belowwww.... thunk

Loadsgood wrote:

I find it wierd that picture are always rectangular... Always. I know I can make an image look a different shape by making it have a transparent background, or colouring its background the same colour as the web page I would be using it on. But I have yet to see a picture-editing program that allows me to change the shape, of the box that the blank picture is in.
Or when I change the resolution of one side of the picture, it changes the other side as well, what the hell?

Who decided that those are the rules? That all pictures are square unless a transparent background is used and that when you change the resolution of one side of the rectangular picture, it changes the size of the other side as well.

You would probably have to start with your own graphics file format first, then work your way up.  I mean down at the binary level, too.  Design/build your own header information, etc.  Something in the format would also have to designate what type of shape it is...would you have a pre-defined list of shapes to choose from (square, circle, ellipse, hexagon)?  Or would you allow the user to rely on a formula for the outer edges?  Then, you would have decide how the pixels are going to be ordered in memory.  Will you paint the picture in typical fashion such as left to right, top to bottom?  Or, in the case of a circle, would you start from the innermost center pixel and spiral your way out (yikes)? 

Then, building a program that handles that format would be probably be easier.  Transformations would be probably be easier, too (scaling, skewing). Also, would it be "vectors" or pixels?

Loadsgood wrote:

I find it wierd that picture are always rectangular...

Most "pictures" are bitmaps, at least in the context in which I think we're discussing this. Something to ponder: If you were inventing a bitmap format would it, in the end, be a rectangular format? Would that make your format easy to understand & use?  How would bitmaps in a non-rectangular format be easy or difficult to use? To measure? To tile? To rotate? To otherwise manipulate?

Here's another puzzling question. If with the honey comb shape, we can have the most inner space with the least material, why do we continue to build retangular houses?

Loadsgood -

Because it is.

Steve.

I would imagine it is because a rectangle has the simplest bounding area, ie. 2 points. Plus it's simpler to store pixel values in a two dimensional array.

Minh wrote:

with the honey comb shape, we can have the most inner space with the least material

O