In this Kivy garden Plot module, a texture parameter is passed to a Line() constructor, and subsequently used for anti-aliasing. I couldn't find any documentation on this argument in the official docs. From looking at the source of Line, it looks like this parameter is not parsed altogether.
Is this a legacy parameter? If so, how was it used and how can this functionality be achieved now?
This works because the SmoothLinePlot is using a custom fragment shader, defined here. This uses the information in the texture to achieve the antialiasing effect.
The normal Line actually does use the texture (actually all VertexInstructions can take a texture parameter and have vertices including texture coordinates), but in a trivial way that doesn't work for more than this antialiasing, and isn't taken advantage of by kivy's default fragment shader. This actually is covered in the source of Line, the texture property is checked here, and the information about what texture coordinates to use is set when constructing the vertices later, e.g. here.
Assuming you're using kivy master (some of these changes are recent, the Line used to only parse the (0,0) coordinate of the texture), I think you should be able to see this in action by assigning a texture to any line. I'm not sure what effect you'll see, as the texture is mapped along line segments, not the whole line, and in a way that may not give visual consistency.
Related
Let's say that I have two Raster objects (or any other Holoviews object really). I can easily visualize one with appropriate color scaling, and I can do a layout to get both figures with the same scaling and coloring. What if I want to do two figures (e.g. because I need them on different pages), but with the same coloring and scaling so that the figures are comparable.
If there's no way to do this automatically, is there any way to access the relevant settings and then feed them manually to the second figure?
If you're using a notebook: The %opts line magic : IPython specific syntax applied globally [string format]http://holoviews.org/user_guide/Customizing_Plots.html and I think hv.opts works globally in script.
For both backends, you can do hv.renderer('bokeh').get_plot(your_element_variable).state (or replace bokeh with matplotlib) and get the original bokeh/matplotlib items.
Then you can use matplotlib's plt.getp() or bokeh's attribute calling (as I've done here https://github.com/ahuang11/holoext/blob/master/holoext/xbokeh.py#L501-L508) to get the base item's color/font/labels/etc.
I'm building a Container using code and now I want to set the Styleusing one UnselectedStyle from the Resource Editor.
I'm doing this because, I don't find the way to add a LinearBackground color and a RoundBorder to my Container. When I put the two properties to the Style, the background color has gone.
So I finally add this Style using the UIManager.getInstance().addThemeProps(String name ThemeFromResource); and later the setUIID(String nameStyle). Is working fine...my Containergets the Style, but the app lose the navigation, the back Commandhas gone.
How can do this? I would like to do with my first way...creating the lineargradient and the border and adding it to the style, but I don't find the way.
I would strongly suggest against doing that.
Border's override other forms of background, round border tries to respect some of them but is REALLY inefficient about that. It effectively draws the background on a mutable image then draws the round border on another mutable image, gets the RGB for both and performs a NOT operation to crop the background into a round image. This (as you might understand) is REALLY expensive in terms of performance, while the image is then cached it is still expensive in the longer term.
You should use image borders which are MUCH faster.
I have a multiviewport OpenGL modeler application. It has three different viewports : perspective, front and top. Now I want to paint a label for each viewport and not succeeding in doing it.
What is the best way to print a label for each different perspective?
EDITED : The result
Here is the result of my attempt:
I don't understand why the perspective viewport label got scrambled like that. And, Actually I want to draw it in the upper left corner. How do I accomplished this, because I think it want 3D coordinate... is that right? Here is my code of drawing the label
glColor3f(1,0,0);
glDisable(GL_DEPTH_TEST);
glDepthMask(GL_FALSE);
glRasterPos2f(0,0);
glPushAttrib(GL_LIST_BIT); // Pushes The Display List Bits
glListBase(base - 32); // Sets The Base Character to 32
glCallLists(strlen("Perspective"), GL_UNSIGNED_BYTE, "Perspective"); // Draws The Display List Textstrlen(label)
glPopAttrib();
I use the code from here http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=13
thanks
For each viewport switch into a projection that allows you to supply "viewport space" coordinates, disable depth testing (glDisable(GL_DEPTH_TEST)) and depth writes (glDepthMask(GL_FALSE)) and draw the text using one of the methods used to draw text in OpenGL (texture mapped fonts, rendering the full text into a texture drawing that one, draw glyphs as actual geometry).
Along with #datenwolf's excellent answer, I'd add just one bit of advice: rather than drawing the label in the viewport, it's usually easier (and often looks better) to draw the label just outside the viewport. This avoids the label covering anything in the viewport, and makes it easy to get nice, cleanly anti-aliased text (which you can normally do in OpenGL as well, but it's more difficult).
If you decide you need to draw the text inside the viewport anyway, I'll add just one minor detail to what #datenwolf said: since you generally do want your text anti-aliased (even if the rest of the picture isn't) you generally want to draw the label after all the other geometry of the picture itself. If you haven't turned on anti-aliasing otherwise, you generally will want to turn it on for drawing the text.
Is it possible to move part of the texture into another texture part without performance hits?
I looked into opengl SDK, but haven't found anything that could do something like this.
glCopyPixels lets you to copy from one framebuffer area into another (I never used it).
glBlitFramebuffer lets you to copy pixels between framebuffers
glCopyTexImage lets you to copy pixels from framebuffer into a texture
Using these function you can accomplish the task by, for example, the following actions:
create FBO, attach texture-1 into the first color channel
bind fbo, set viewport to contain the source area
call glCopyTexSubImage into the texture-2 to get the contents
I've been stumbling over this for a while and was wondering if anyone has run into this problem before.
The application I'm working on is divided into multiple data plots and a single timeline at the bottom of the screen. Each plot (which is actually multiple textures layered on top of each other) as well as the timeline is rendered to a separate texture. The timeline texture is rendered first, followed by each of the plot textures from the top of the screen to the bottom. I am using DXUT and DirectX9 (March 2009).
After adding time text to the timeline texture, I noticed that the text was repeated in the title bar of every data plot. Here's a screencap of a portion of the display, it shows just a single plot, but the text repeats on every plot opened:
It seems like it is tied directly to the DrawText being called in the timeline's render function. I do use relative coordinates as the rect being passed to DrawText, but since I've already set the render target to the desired texture it should only affect the current texture. Not every texture rendered afterward.
Has anyone ever run into any problems similar to this using D3DXFont?
EDIT: After some more experimentation, it looks like it has something to do with the Z buffer. By adding D3DCLEAR_ZBUFFER to the clear on each texture surface, the duplicate text is gone. While the problem seems bypassed for now, I'm still curious as to why the Z buffer for a completely separate texture was being written during my DrawText call.
The Z Buffer state is persistent.
For example,
SetDepthStencilSurface(X)
SetRenderTarget(A)
Draw()
SetRenderTarget(B)
Draw()
Both Draw calls will use the same depth buffer.
The DrawText is not changing the depth buffer that you have set. It assumes you meant to do what you did.