I'm using Pango for text layouting without the cairo backend (currently testing with the win32 backend). And I like to know if pango is capable of a flow layout around an image, or any given container. Or maybe inside a custom container.
Something like this: Flow around image
I have checked many examples and the Pango API and didn't found such a feature. Maybe I'm missing something or Pango does not have this feature.
As I said in this answer, you can't. I went through the source code Pango graphics handling is primitive to the point of uselessness. Unless there's been some major reworking in the past year, which the release notes don't indicate, it's probably the same now.
The image you provide as an example is only available as PDF at the moment which requires every line, word and glyph be hard-positioned on the page. While theoretically possible to check the alpha channel of the image to wrap the text around the actual image instead of the block it contains, this has not (to the best of my knowledge) ever been implemented in a dynamic output system.
Pango, specifically, cannot even open "holes" in the text for graphics to be added later and, at the code level, doesn't even have the concept of a multi-line cell - hence a line being the size of its largest component.
Your best bet is to look at WebKit for more complex displays. I, for one, have pretty much given up on Pango and it seems to be getting less popular.
Related
I've read Rendering Vector Art on the GPU on rendering shapes that are defined by quadratic/cubic Bezier curve boundaries. I was hoping to build off of this to create text that fills in as if it were stroked by a pen or brush somehow. (Any advice on how to do this is welcome.)
However, I'm a little unsure of where to get my hands on fonts / shapes that have the format specified in this paper (arrays of points representing quadratic/cubic Beziers).
Does anyone know of a way of getting font/vector drawings that are in this format? The authors of the paper mention truetype fonts, but according to
TrueType Font Parsing in C
it looks like parsing truetype fonts might involve a lot more than this? I know there are also formats like .svg, but I am not sure where to start with that, since it holds so much more than what I am looking to get out of it.
As an example, is there some type of file format that I could convert a .svg file or truetype file to, perhaps by using something inkscape's export function, such that the resulting format would be possible to parse for an array of points and control points?
I accepted an answer below, but for anyone interested in this, you should check out
https://github.com/quarnster/TTF
It's pretty much exactly what I was looking for. The code works great, but it's a bit hard to understand how to use it. It makes more sense if you read about the TTF format, like here An Introduction to TrueType Fonts: A look inside the TTF format.
I suggest using the cross platform library FreeType (http://www.freetype.org/). FreeType loads font files and, among other things, provides the bounding curves of glyphs in the typeface. Specifically, you should look into the function FT_Outline_Decompose, which gives exactly what you want.
I started working at this company that uses an 2D OpenGL implementation to show our system's data (which runs on Windows.) The whole system was built with C++ (using C++Builder 2007). Thing is, all the text they print there are pixelized when you zoom in, which I think happens because the text is a bitmap:
From what I know they use the same font files as Windows does. I asked around here on why this happens and the answer I got is that the guy who implemented it (which doesn't work at the company anymore) said fonts on OpenGL are hard and this was the best he could do or something like it.
My question is: is there any simple and effective way to make the text also a vector (the same way those lines in the picture are?) So when I zoom the camera, which happens a lot, they don't pixelize. I have little knowledge of OpenGL and if you have some guide and/or tutorial related to this to point me towards the right direction I'd be very thankful. Basically any material would be great.
Most of OpenGL text rendering libraries come to this: creating bitmaps for the fonts. This means you are going to have problems with scaling and aliasing unless you do some hacks.
One of the popular hacks is Valve's approach: Chris Green. 2007. "Improved Alpha-Tested Magnification for Vector Textures and Special Effects.". You use signed distance field algo to generate your fonts bitmap which then helps you to smooth the text outlines on scale during rendering. Wikidot has the C++ implementation for Distance field generation.
If you stick to NVidia specific hardware, you can try the NVidia Path extension which allows you to render graphics directly on GPU. Remember, it is a NVidia only thing.
But in general, signed distance field based approach is the smoothest and easiest to implement.
BTW, freetype-gl uses Valve's approach and also the modern pipeline.
You can try freetype-gl its a library for font rendering in OpenGL.
The issue with using fonts in OpenGL is that they are handled inconsistently across platforms, and that they have minimal support. If you're willing to go with a helper library for OpenGL (SDL comes to mind), then this behaviour will likely be wrapped, meaning that you merely need to provide a suitable font file for them to use.
You may try out FTOGL4 , the fonts for OpenGL4
I recently saw the virtual mirror concept on you tube, I tried it out and researched about it. It seems that the creators have used augmented reality so that people can see the output on their screens. On researching I found out that we identify a pattern on which a 3D image is superimposed.
Question 1:How are they able to superimpose the jewellery and track the face of the person without identifying any pattern?
I also tried to check various libraries that I can use to make a program similar to the one they show. Seems to me that a lot of people are using Android phones and iPhones and making apps that use augmented reality.
Question 2:Is there any way that I can use c++ and try to make a program that uses augmented reality?
Oh, and the most important thing, the link to the application is provided below:
http://www.boutiqueaccessories.com.au/virtual-mirror/w1/i1001664/
Do try it out. Its a good experience. :D
I'm not able to actually try the live demo, but the linked video suggests that they either use some simplified pattern recognition (get the person's outline), or they simply track you based on the initial image (with your position/texture being determined by the outline being shown.
Following the video, it's easy to see that there's no real/advanced AR behind this. The images are simply overlayed or hidden (e.g. in case it's missing track of one ear due to you looking to the side) and they're not transformed (no perspective or resizing happening). They definitely seem to track the head (or features like ears, neck, etc.). depending on your background and surroundings that's actually a rather trivial task.
Question 2: Sure! There are lots of premade toolsets out there, but you could as well use some general image processing library such as OpenCV to do the math. Augmented reality usually uses some kind of pattern (e.g. a card or page with a known pattern) to determine the correct position and transformation for the contents to be added to the image. There are also approaches using the device's orientation and perspective changes in camera images to determine depth/position (I really like this demo).
I'm doing an implementation for a path planning algorithm. I'd really like to be able to load in a 2d "environment" in vector graphics (svg) format, so that complex obstacles can be used. This would also make it fairly easy to overlay the path onto the environment and export another file with the result of the algorithm.
What I'm hoping to be able to do is use some kind of library in my collision test method so that I can simply ask, "is there an obstacle at x, y?" and get back true or false. And then of course I'd like to be able to add the path itself to the file.
A brief search and a couple of downloads left me with libraries which either create svg's or render them but none really gave me what I need. Am I better off just parsing the xml and hacking through everything manually? That seems like a lot of wasted effort.
1.This may be a bit heavyhanded, but Qt has a really great set of tools called the Graphics View Framework. Using these tools, you can create a bunch of QGraphicsItems (polygons, paths, etc..) in a QGraphicsScene, and then query the scene by giving it a position. Using this you'll never actually have to render the scene out to a raster bitmap.
http://doc.trolltech.com/4.2/graphicsview.html, http://doc.trolltech.com/4.2/qgraphicsscene.html#itemAt
2.Cairo has tools to draw all sorts of shapes as well, but I believe you'll have to render the whole image and then check the pixel values. http://cairographics.org/
The SVG specification includes some DOM interfaces for collision detection:
http://www.w3.org/TR/SVG/struct.html#_svg_SVGSVGElement__getEnclosureList
http://www.w3.org/TR/SVG/struct.html#_svg_SVGSVGElement__getIntersectionList
Using these methods, all "obstacles" (which can be groups of primitive elements, using the <g> element) should be labelled as a target of pointer events.
These methods are bounding-box based, however, so may not be sophisticated enough for your requirements.
Thanks for the responses. I didn't manage to get anything working in QT (it's massive!) or Cairo, and I ended up going with PNGwriter, which does pretty much what I wanted except, of course, that it reads and writes PNG's instead of vector graphics. The downside here is that my coordinates must be rounded off to even pixels. Maybe I'll continue to look into vector graphics, but this solution is satisfactory for this project.
For those not familiar with Core Image, here's a good description of it:
http://developer.apple.com/macosx/coreimage.html
Is there something equivalent to Apple's CoreImage/CoreVideo for Windows? I looked around and found the DirectX/Direct3D stuff, which has all the underlying pieces, but there doesn't appear to be any high level API to work with, unless you're willing to use .NET AND use WPF, neither of which really interest me.
The basic idea would be create/load an image, attach any number of filters that can be chained together, forming a graph, and then render the image to an HDC, using the GPU to do most of the hard work. DirectX/Direct3D has these pieces, but you have to jump through a lot of hoops (or so it appears) to use it.
There are a variety of tools for working with shaders (such as RenderMonkey and FX-Composer), but no direct equivalent to CoreImage.
But stacking up fragment shaders on top of each other is not very hard, so if you don't mind learning OpenGL it would be quite doable to build a framework that applies shaders to an input image and draws the result to an HDC.
Adobe's new Pixel Blender is the closest technology out there. It is cross-platform -- it's part of the Flash 10 runtime, as well as the key pixel-oriented CS4 apps, namely After Effects and (soon) Photoshop. It's unclear, however, how much is currently exposed for embedding in other applications at this point. In the most extreme case it should be possible to embed by embedding a Flash view, but that is more overhead than would obviously be idea.
There is also at least one smaller-scale 3rd party offering: Conduit Pixel Engine. It is commercial, with no licensing price clearly listed, however.
I've now got a solution to this. I've implemented an ImageContext class, a special Image class, and a Filter class that allows similar functionality to Apple's CoreImage. All three use OpenGL (I gave up trying to get this to work on DirectX due to image quality issues, if someone knows DirectX well contact me, because I'd love to have a Dx version) to render an image(s) to a context and use the filters to apply their effects (as HLGL frag shaders). There's a brief write up here:
ImageKit
with a screen shot of an example filter and some sample source code.