I am now writing a image viewer, It is used for view thumbnails.
As it is ugly, I decide to draw shadow round thumbnail.
There is background color.
I am using StretchDIBits to draw a shadow image at the location of thumbnail.
However it is really annoying that it cover the background color...
When the background is white, it looks perfect.
but if the backgound is not white, it has a white border.
so I make use of AlphaBlend, first draw the shadow image onto a DC, then use AlphaBlend onto the background. However, I can still see the white border.
Is there any why to generate a perfect shadow , no matter what background is.
Are you sure the shadow bitmap contains alpha values for the alpha channel ? I.o.w.: how are you creating the shadow bitmap: are you doing that by blurring a square on a transparent target or a white target? If the first, the shadow bitmap contains an alpha channel and should blend fine with the background. if the second, your shadow bitmap contains white fragments and thus will blend that white with the background.
Related
I am applying a canvas as a texture to a plane. And it looks fine (The background is white by default) if I am displaying it within a browser itself.
But as I change to Virtual Reality Mode the background of the canvas is changing to black.
I know that i can place a white rect to have a white background, but this is not feasible due to performance issues.
Are there any other solutions to tackle this problems?
Thanks!
Try filling in the canvas as white (fillRect), or adding a background to the scene itself (<a-sky color="#FFF">). Let me know if that works, or provide a JSFiddle for us to play around.
I have an image that is a simple coloured text on a black background. Is there a CSS filter (or a hacky combination of filters) that would allow me to turn black colour into complete transparency (essentially leaving me with just text)?
In short
I'm trying to get the text in my QLabel to paint as if it were over a black background, ignoring the real background colour.
In depth
I have a QLabel in a green coloured widget, the text is anti-aliased and white, the anti-aliasing softens the edges of the text by blending with the green background colour.
Hardware detects the exact green colour and uses it like a green screen to display some techno-wizardry without also drawing over my software overlay, it makes the background look black.
The anti-aliased text has a fuzzy green halo where it has slightly changed the green colour and hardware doesn't overwrite it.
I want the text to be draw as if it were over a black background
What I've tried
I have tried using a black opaque QGraphicsDropShadowEffect to be drawn under the text, thus giving the text a black background to draw on, this led to a bigger green halo around the text.
I have tried setting various QBrushes in the label's QPalette for the Qt::WindowText and Qt::Base ColorRoles.
I have re-implemented the paintEvent and I am trying to use style()->drawItemText(... ) to avoid re-implementing all the helpful alignment code.
I have tried intercepting the QStyleOpt parameter and setting its QPalette's background colour to black, however that didn't change anything, I still get fuzzy, greenish text.
I have tried various QBrush and QPen colours in the QPainter.
I'm really close using a QPainterPath in an overidden paintEvent function (in a class extending QLabel) where I paint a black path of the text behind the text, then I call QLabel::paintEvent and let it draw the text over the top. The issue here is that in some cases the path is clipped to smaller than the widgets rect() on the left hand side, scope for another question I think!
What I could try but haven't worked out yet
I could give the text a black outline as per this question however I'm using a QWidget not a QGraphicsView text item, and then the black outline would still probably blend with the green background.
Compromises I've already thought of and want to avoid
I could set the QLabel background to black, leaving large rectangles of black over the resulting overlay, unfortunately the labels are often much larger than the text being displayed.
I could stop the font being anti-aliased, this looks quite ugly and it stops all fonts being uniform across the product.
In an image like this, I want to remove the white background but keep the grayness of the dropshadow. Reomving mapping the actual image is not a problem!
This is what I enden up doing instead after lots and lots of trial and error.
Duplicate the layer with the paper in it.
Invert the new layer.
Painting the "paper-part" clear white
Using the inverted layer as a mask on the first layer.
Worked like a charm, perfect masking!
Two options that I can think of:
a) Edit the image in photoshop and make the background transparent.
b) Overlay the "white" background w/ a div overlay that has a white background.
a is the preferred option. Post a comment on this reply if you need me to do this for you.
did you make that image? Why not make the image on a transparent background?
But if you didn't make the image, I don't know if you really can unless you plan on putting it on another whitish background because the dropshadow itself is going to be a little transparent and whatever is underneath it will show through.
Anyone know where I can find the Microsoft guidelines for creating WPF gel-type buttons? I'm not sure if "gel" is the correct name for this effect but I have heard many people use the term. If MS doesn't have a guideline, do you have some other standards or guidelines for creating these buttons?
Have a look at the glass button.
There are a number of XAML elements
which go into making up the button.
They are clearly commented in the XAML
but the list is as follows:
Drop-shadow: an ellipse with a radial gradient of black fading to
tranparent
Button surround: a white ellipse slightly bigger than the green one
Black button background: only visible round the edges of the green
when the button is pressed
Main button colour: the green (or whatever color you want) of the
button. This ellipse is clipped to
its initial outline, thus allowing us
to move the ellipse slightly for the
button press without it overlapping
the button surround
Top glow: an ellipse with a linear gradient background of white (at the
top) fading to transparent. Smaller
than the main button colour and
positioned so that the tops are the
same
Bottom glow: an ellipse the same size as the main button colour but
with a linear gradient background of
white (at the bottom) fading to
transparent. This is also clipped as
per the main button colour.
Hover-over glow: an ellipse the same size as the main button colour
with a radial gradient background of
white (at the centre of the ellipse)
fading to transparent. This is
initially transparent.
Transparent element for catching mouse events: on top of all of this is
a transparent ellipse the same size as
the white button surround for catching
MouseEnter, MouseLeave,
MouseLeftButtonDown and
MouseLeftButtonUp events. This
element also contains the Storyboard
for the pulsating hover-over effect
(although this could be in any XAML
element).