My Widget declares:
setAttribute(Qt::WA_NoSystemBackground);
In its paintEvent, I set:
painter.setOpacity(0.75);
This gives me the ability to project a png on its entire background with some transparency. This works well.
Problem: I am adding a QPushButton with a transparent png on top of my widget. The opaque portion of the button's image (derived from Qt CSS) is shown correctly, and the transparent areas remain with my widgets' drawn background, which is already somewhat transparent. When I HOVER over the image, my css dictates that my QPushButton changes image. When that happens, the opaque portion of the button image is shown correctly, but for the transparent areas, it's as if my own widget is re-drawing the background image, only with full opacity.
This happens only on Windows. On OS X is works fine. I was wondering whether there was a bug in Windows in that respect and if there's a workaround for it.
Turns out that while
setAttribute(Qt::WA_NoSystemBackground);
is good enough for OS X…
On windows you should also add:
setAttribute(Qt::WA_TranslucentBackground);
That took care of it. Problem resolved.
Related
At the moment, I am programming a little map editor for my 2D-RPG game.
All functions are successfully implemented, but my problem is, that the textures for each cell in my QTableWidget aren't stretched to the full size of 32x32. I have already changed the sizeHint settings, but it doesn't work.
Here a little picture about my problem.
As you can see, in each cell are a white background and the textures aren't fully stretched. Actually I load the textures over the setIcon function, maybe an other way exists to load images in a cell? How can I fix it, for stretching to the full size of 32x32?
Try to style the icon or see where its padding/margin gets defined.
Google Chrome always seems to be changing the color of an image that I'm trying to match to a background color. I tried saving it in Photoshop and GIMP and even adjusted the color settings in each but it doesn't help in Chrome. FF and IE work fine (for once).
The color of my image is #282828. After I saved it as a PNG, I reopened it in both GIMP and Photoshop and used the eyedropper tool to confirm that the color was still #282828. When it renders in Chrome it's darker. I have a div with a background color of #282828, and the image is right next to it. I took a screen shot and the div's background color was #282828 and the images background color was #1d1d1d. I tried this for several different colors and each has had the same result. I even tried making the source image the color Chrome was rendering it as but Chrome still changes it. So for example, since Chrome was changing #282828 to #1d1d1d, I made the source image #1d1d1d, and when I rendered it in Chrome it was not #1d1d1d, but some other darker color.
At this point, I'm looking for either a fix or a programmatic work-around. Because the image is transparent, has curves, and a drop-shadow, there's really no way for me to avoid replacing the it, or even parts of it, with html.
Update:
I also tried saving it as a jpg and gif. gif actually works but can't preserve the drop shadow. The image I'm using is attached. If I take a screenshot of this in Chrome, GIMP's eyedropper tool says it's #1d1d1d. If I open the original and do the same, it's #282828.
PNG uses gamma correction to try to ensure that the image looks kinda the same across all monitors, and this can cause color mismatches like the one you're seeing. It's a combination of image editor issues and browser issues: image editors are not forced to embed gamma data inside images, and browsers are free to ignore the gamma correction if it's there and free to enforce some at random when it's not there. In this case, I'd rather think that Firefox ignores it.
Use a transparent PNG if you don't want its background to interfere with your page's background.
[EDIT] For your specific case, you may be able to replicate the graphics you're looking for by styling elements, using border-radius and box-shadow, two widely-implemented CSS3 properties that reasonably decay on older browsers.
My Qt version is 4.7.1 and I want to set the background color of a QLineEdit the same as window color, and I use this way:
QString bgColorName = palette().color(QPalette::Normal, QPalette::Window).name();
QString strStyleSheet = QString("QLineEdit {background-color: ").append(bgColorName).append("}");
ui->lineEdit->setStyleSheet(strStyleSheet);
I tried to get the background colors name and then set the stylesheet of the QLineEdit, however, after running the application, I found the QLineEdit's color is a little different, that is, if you look at it carefully, you can see the difference, both on Win7 and Mac.
Could anyone help me to find a way to get the right background color of the dialog, thank you in advance.
The code you posted actually works for me (using Windows 7). Have you verified with an image editor such as Photoshop that the background of the line edit isn't the same as the dialog? Sometimes the mind plays tricks and can think the background color is different (due to the border) when in fact it isn't.
By the way, you can just make the background of your QLineEdit transparent using style sheets like this:
QLineEdit le("Line Edit with transparent BG");
le.setStyleSheet("background:transparent;");
I have some CSS for displaying a reflection on an element which uses -webkit-gradient to fade out:
.foo { -webkit-box-reflect: below 0 -webkit-gradient(linear, left top, left bottom, from(rgba(255, 255, 255, 0)), to(rgba(255, 255, 255, 0.5)), color-stop(0.7, transparent)); }
On browsers which support -webkit-box-reflect such as chrome, this displays a reflection of the element which gradually fades out as expected.
On browsers which don't support it at all, no reflection is show.
However, on Android's browser, a reflection is shown, but doesn't fade out.
Is there any way of getting Android to either:
fade out the reflection, or
not show the reflection at all.
I know I could use javascript to detect the browser and change the style accordingly, but I'd much prefer a CSS-only solution.
Without an example file or link, it is a little difficult to see what you need.
I also played with some reflection stuff a few months ago and didn't find anything that could do what you describe. I have some steps to get you what you want, outside of code. I recommend the item you wish to reflect be a PNG on a transparent background, to start.
The steps:
1.Take the image into your favorite image manipulation program (ex. Photoshop)
Double or extend the image canvas the necessary amount to include the reflection in the appropriate direction
Duplicate the layer (Photoshop-Layer/Duplicate Layer)
Reflect the image. (Photoshop-Layer/Image Rotation/Flip Canvas (your direction))
Move the duplicated layer such that it appears as a mirror using the Move tool
Select the Marquis tool, and set the edge blur to about 50% of your original image width.
Drag your cursor over the "reflected" layer, don't worry if it says the selection lines won't be visible, unless it says nothing was selected. If it says nothing was selected, reduce your edge blur to about 25% and try again.
Once you have a selection, be it visible or not, delete the selected area. This should give you a "reflected" look.
If desired, add a background on a layer below everything else.
Save your image as a jpg if you don't have a transparent background or a png if you do. Use it in place of the image you were reflecting and fading with code. This will be mostly browser compatible.
CSS isn't designed to handle stuff like that. In other words: no, it's not possible.
I'm having similar problems trying to do things with background gradients in the Android browser, and it appears completely unsupported
Unfortunately the above answer is right, there isn't a way to split your declaration up in a nice progressively enhanced way. You could use JavaScript/modernizr as you mentioned, and at least set a support class(es) so you don't actually have to flip the style within code.
You could try reproducing this effect with a HTML canvas element, using drawImage with your image and transforming it. Although canvas can be slow in mobile webkit.
Good luck
do gradients work at all in the android browser?
if they do, make sure you're using the correct version. There's an old webkit format you may need to use.
If not, just use modernizr to hide it on places that don't support gradients.
I have a canvas which I want to accept drags on.
I have added a dragOver and dragEnter event listeners to the canvas, but they only work if I drag over something inside the canvas (another child element).
I realised that if I set the canvas' background colour to black it works. So I have set it's background transparency to 0, which works... buy is there a better way to work around this apparent need for the canvas to have something inside it to accept dragEvents.
Thanks
Rob
According to one of the Flex developers, "In Flash there is a difference between a transparent pixel and an area in a Sprite that hasn't been drawn on at all." (http://www.mail-archive.com/flexcoders#yahoogroups.com/msg127690.html)
I'm guessing this is the reason why you need to have the transparent background. For what it's worth, this is always the way I've seen this problem solved. There is also this question which talks about this problem.
Hope this helps!