I want to resize images with different sizes with rmagick using only the width. I need to keep the proportions in example 640px width. The point is, if image is bigger than 640px, it should be made smaller to 640px. However, if the image is smaller than 640 it should not scale to 640, it should do nothing.
I thought this was the purpose of change_geometry, but somehow is not working for me. This is my example, but it´s always scaling all images to 640px.
photo = Magick::Image.read(name).first
photoMedium = photo.change_geometry!("640") { |cols, rows, img|
img.resize!(cols, rows)
}
# ... write photoMedium
UPDATE:
Well, I thought that was the purpose of change_geometry. Anyway, I guess you can always check the columns and if it´s bigger than 640 the resize, otherwise do nothing.
Check out the resize_to_fit method.
Related
I am using NextJS and react-pdf/renderer and my tool creates a PDF and I'd like to display it with the PDFViewer component.
The Viewer loads but only takes up a small part of the screen. Whenever I change the 'width' and 'height' attribute with relative values (100%, 100vh), it won't take it. The only way to force it, is to put specific pixel values in it, but that defeats the purpose of being responsive to the screen size.
Sandbox that reproduces my issue: https://stackblitz.com/edit/nextjs-su5bi1?file=pages/index.js
Does anyone have an idea why this is happening?
Here is your screen with a red block of pixels of 150 pels high, note how it matches exactly your frame height.
Generally you ONLY set frame height in pixel units (The cross browser default minimum is 150?) you probably need somewhere to set a style defining the height as a different number of pixels.
see comment 2 in https://stackoverflow.com/a/73201090/10802527
We had a strange problem with blurred images under Retina displays. Left part of the image - before, right one - after the fix.
Our QML code was using this code to show images:
Image {
anchors.verticalCenter: parent.verticalCenter
sourceSize.width: 25
sourceSize.height: 25
source: preview.url
}
I've tried to multiply sourceSize by Screen.devicePixelRatio - images became bigger so they did not fit their places.
Then I've replaced sourceSize.width with just width and the same for height. So:
Image {
anchors.verticalCenter: parent.verticalCenter
width: 25
height: 25
source: preview.url
}
And it works fine now.
My questions are:
Is it required to multiply sourceSize by devicePixelRatio? Or is it managed automatically? It seems that it is managed automatically for PNG and NOT managed for SVG.
If it is already managed automatically for PNG (these images preview.url are PNGs) then why was it blurred? The original PNG image is of size 64x64 pixels.
Why did images become bigger after I've multiplied sourceSize by devicePixelRatio?
Addition #1. I'm using data:// scheme in images' URLs. I.e.
QString url("data:");
url += imageMimeType;
url += ";base64,";
url += imageData.toBase64();
While referring to the other answer I gave you here, my understanding of the Qt code is that, outside from the cases described here, Qt does no scale that value. So my understanding seems to be the opposite of what you state in 1. What evidences led you to that statement?
Assuming this concept is correct (I may be incorrect), the reason for point 2, would be that Qt is loading a size that would be appropriate for 1x scaling. But for higher factors, there is a quality loss. If you are on retina, then you should adjust that value, or provide the #2x version.
As for point 3, the reason is probably in the docs: "if the width and height properties are not specified, the Image automatically uses the size of the loaded image". So if you double the size of the loaded image, you double the size of the element, as you are not setting width and height explicitly.
Setting width and height solves the problem because the image is loaded in full size, so it can draw with proper quality after the scaling.
Hope someone else can correct me if my understanding of Qt code is wrong.
There is one simple task I want to achieve.
I have an image in a variable width container.
The container can have a width of 300, 400, 700, or 900 pixels. This is done by the means of media-queries
The image should take up all the width of that container. So it will be also 300, 400, 700, or 900 pixels wide.
The image should have different sources for all that width values. So I can serve smaller images on mobile phones.
I thought that this could be done with the srcset attribute of the img element, maybe under help of the sizes attribute. width something like this
<img src="http://dummyimage.com/300x200/abc/000"
alt="dummy"
srcset="
http://dummyimage.com/900x200/abc/000 900w,
http://dummyimage.com/700x200/abc/000 700w,
http://dummyimage.com/400x200/abc/000 400w,
http://dummyimage.com/300x200/abc/000 300w
"
/>
But it's not working in that way, because the browser chooses the image in proportion to the width of the display port and not to that of the image itself.
Example with use of picturefill polyfill from http://scottjehl.github.io/picturefill/: http://codepen.io/HerrSerker/pen/itBJy . This does not work, because it will take the one image that is the next size.
I could of course take that into account and change my srcset to this
srcset="
http://dummyimage.com/900x200/abc/000 999999w,
http://dummyimage.com/700x200/abc/000 900w,
http://dummyimage.com/400x200/abc/000 700w,
http://dummyimage.com/300x200/abc/000 400w
"
This will work on the desktop, but fails on retina displays, because the device pixel ratio is taken into account here, but in a different way than with the media queries. And it is not useful, because the image should know about the width of the viewport and of the same width and that at compile time? No way. Image I use the image in a grid system. The image has different widthes if I'm in a 3 column grid on desktop devices and a 1 column grid on smart phones. That should not be in the responsibility of the image to calulate the ratio of width and viewport-width.
I did not have any luck with the sizes attribute as well (no example here). The reason is tha same as above. In the sizes attibute I say which amount of the viewport width should my image be wide according to media queries. This is so off. How should the image know?
So I came around with this solution. I setup a data-srcset attribute with the same syntax as the srcset attribute itself, but with a custom JavaScript programming. Example here: http://codepen.io/HerrSerker/pen/tCqJI
jQuery(function($){
var reg = /[\s\r\n]*(.*?)[\s\r\n]+([^\s\r\n]+w)[\s\r\n]*(,|$)/g;
var regw = /(.*)w/;
var sets, $set, set, myMatch, i, w, that, last;
var checkData = function() {
$('img[data-srcset]').each(function() {
that = $(this);
$set = that.data('srcset');
sets = [];
while(myMatch = reg.exec($set)) {
set = {};
set.src = myMatch[1];
set.w = (myMatch[2].match(regw))[1];
sets[set.w] = set;
}
w = that.width();
last = 0;
for (i in sets) {
last = i;
if (w <= i) {
that.attr('src', sets[i].src);
return;
}
}
that.attr('src', sets[last].src);
});
};
checkData();
$(window).on('resize', checkData);
});
This works, but it feels wrong. But maybe not, as the specifications says for responsive images to behave just in the way that it does. But I feel that it's the wrong way. 90 % of use cases for responsive images won't work with the spec.
So am I wrong? Didn't I use the srcset in the defined way? Did I understand the spec incorrectly? And do the W3C and Responsive Images Community Group think in such a way apart from reality?
Are the smaller images scaled down versions of the bigger image? Or are they cropped (art direction)? If the latter, you should use picture and source media.
The reason the browser only uses the viewport for deciding which image to download is that it's the only thing that is available when the browser wants to download an image. The CSS (probably) isn't downloaded yet. So if you use srcset+sizes, you have to repeat the breakpoints and image widths in sizes.
This question seems like a duplicate of Responsive full width image banner with fixed height using srcset
Like zcorpan said, what you are trying to do falls under the "art-direction" use-case (since the different images have different proportions), so you should use the <picture> element, rather than srcset. See the other question's answers for a syntax example.
I'm trying to make my UI content expand nicely when the user resizes the window. I'm doing this in Qt Designer and learning about layouts and size policies.
Seems that everything is working fine for now: one layout stays within its maximum size, while another expands with the window resize, and they all stay above their minimum sizes. That's great and all, but the problem is that if I have a list with a lot of items, or if I am displaying a very large image, it will expand beyond the available window space and cause the window to be huge.
How can I specify something along the lines of "do not expand beyond the available window space"? I've played around with the size policies, but I couldn't get it to work. Is this something I need to set for the form itself rather than the layouts it contains?
I should specify this is the desired behavior: Display the widget as large as the available window, even if the widget content is too small. Expand/Shrink the widget to fill the window when the window is resized. Do not expand beyond the available window space. The widgets in question are 2 images (labels) and 1 list view.
I set the size policy to "ignored" for the respective widgets. That fixed it.
Or you can set the window maximum size.
I am wondering if it is possible to shrink an image widget down to a size that is smaller than the image resource itself. I have tried the following:
imageResource.setSize(size, size);
imageResource.setPixelSize(size, size);
I have also tried re-sizing in the CSS file. But when I size the image to smaller than the original, it just crops it down and doesn't actually shrink it. It seems to me the solution is to use a high resolution, smaller image that I can scale up if need be, but I feel like I'm missing something here.
You can use CSS3 background-size property to scale the image:
http://www.w3schools.com/cssref/css3_pr_background-size.asp
Note that it's not supported in some very old browsers.
You can also try with,
ImageResorce myImage = new ImageResource();
myImage.getElement().setAttribute("height","20px");
myImage.getElement().setAttribute("width","20px");
cheers !!!