Pretty much it -- is there any way to do it platform-, respectively, backend-independently? In MATLAB, say, it's not a problem, whereas matplotlib doesn't even seem to support different units but inches.
If you know the dpi of your screen you can convert inches to pixels. But it will work only for screens with the same dpi. Otherwise you have to work with the backend to get the correct size and position of the figure canvas on the screen in pixels
Related
I have some 1000x1000 images where one pixel is 1 and the rest 0. My issue is that I can't even see the location of the high pixel using imshow() unless I zoom in all over the place to look for it. I assume it is doing a nearest lookup when decimating to screen resolution. Is there any trick I can use to get around this? I know I can convolve with a kernel of some kind to expand the point, but this is a little bit expensive computationally, and if I zoom in it won't look correct.
In matplotlib, if I see the aspect ratio of the image using
ax.set_aspect('equal')
is there a way I can get the actual figure to also match that? Currently, I just get a lot of grey space.
I'm importing my stimulus from a folder. I would like to make them bigger *the actual image size is 120 pix (height) x 170 pix (width). I've tried to double the size by using this code in the PsychoPy Coder:
stimuli.append(visual.ImageStim(win=win, name='image', units='cm', size= [9, 6.3],
(I used the double number in cms) but this distorts the image. Is it any way to enlarge it without it distorting, or do I have to change the stimuli itself?
Thank you
Just to answer what Michael said in the comment: no, if you scale an image up, the only way of guessing what is in between pixels is interpolation. This is what psychopy does and what ANY software would do. To make an analogy: take a picture of a distant tree using your digital camera. Then scale the image up using all kinds of software. You won't suddenly be able to see the individual leaves since the software had no such information as input.
If you need higher resolution, put higher resolution images in your folder. If it's simple shapes, you may use built-in methods such as visual.ShapeStim and it's variants: visual.Polygon, visual.Rect and visual.Circle. Psychopy can scale these shapes freely so they always stay sharp.
I'm working with documents, so maintaining the the original image dimensions and subsequent dpi is important.
The aspect ratio is always maintained so the automatic fill modes and alike don't seem to have any effect.
Say I have a 300 dpi document and the user want to clear an inch border around the image. So I need an inch cropped from the image but the result needs to be the original image dimensions (2550x3300).
I have been able to achieve this effect with...
...&crop=300,300,-300,-300&margin=300,300,300,300
This works, but seems more than a little clunky. I've tried a lot of other combinations but they all seem to enlarge or reduce the image size which is undesirable in my case.
So does someone know a simpler syntax to achieve the desired result, or do I need to re-size the image then calculate and fill with a margin as I'm doing now.
Thanks
It turns out that my example requests the image in it's full size which turns out to be a special case. When I introduce a width or height into the command line things don't work very well since crop size is in respect to the original image dimensions and margin size is in respect to the result image.
Thinking about it more I abandoned the crop approach. What I really needed was a way to introduce a clipping region into the result bitmap. So I built an extension to do just that. It works well as it doesn't interfere with any of Resizer's layout calculations and the size of the returned image is whatever the height or width were specified as. Which is just what I needed. The Faces plugin has an example of introducing a clipping region.
Karlton
Cropping and re-adding 300px on each edge is best accomplished exactly the way you're doing it:
&crop=300,300,-300,-300&margin=300
What kind of improved syntax would you expect? This isn't a common operation.
I have an app that creates a large bitmap and later the user can add some labels. Everything works great as long as the base bitmap is the default 96x96 resolution. If I bump it up to 300 for instance, then the text applied with Graphics.DrawString is much too large - a petite size 8 or 10 font displays like it is 20.
On the one hand, it makes sense given the resolution increase, but on the other, you'd think the Fonts would scale. MeasureString returns a larger size when measured on a 300 vs 96 dpi bitmap, which wasn't really what I expected.
I've tried tricking it by creating a small bitmap of the appropriate size, printing to it, then pasting that to the master image. But when pasted to the high res it enlarges the pasted image.
The only other thing I can think of is to create a high res temp bitmap, print to it, then shrink it before pasting to the main image. That seems like a long way to go. Is there a compositing or overlay type setting that allows this? Are font sizes only true for a 96 dpi canvas?
Thanks for any hints/advice!
The size of a font is expressed in inches. One point is 1/72 inch. So if you draw into a bitmap that has 300 dots-per-inch then your font is going to use a lot more dots for the requested number of inches. So when you display it on a 300 dpi display then you'll get the size in inches back that you asked for.
Problem is, you are not displaying it a 300 dpi device, you are displaying it on a 96 dpi device. So it looks much bigger.
Clearly you don't really want a 300 dpi bitmap. Or you want to draw it three times smaller. Take your pick.
If you want a consistent size in pixels, specify UnitPixel when creating your Font object.