transformation

问题 I am trying to rotate a QGraphicsPixmapItem child. For other QGraphicsItem , rotation and scaling work fine. But for a QGraphicsPixmapItem , if the size does not keep aspect ratio, instead of rotation I get shear. sample code: #include <QApplication> #include <QGraphicsView> #include <QMessageBox> #include <QGraphicsPixmapItem> #include <QFileDialog> int main(int argc, char *argv[]) { QGraphicsScene s; s.setSceneRect(-200, -200, 500, 500); QGraphicsView view(&s); view.show();

问题 I'm transforming a parser for v8 in NodeJS. Currently I have the following structure struct Node { short tag; std::string data; Node(std::string input, short tagId) { tag = tagId; data = input; } }; std::vector<Node> elems; And I'm populating the vector from loop like this: elems.push_back(Node(STRING, 3)); My goal is return a javascript object like this: [ { tag: 2, data: "asdsad" }, { tag: 2, data: "asdsad" }, { tag: 2, data: "asdsad" } ] But since the V8 documentation is crappy, I couldn't

问题 I have a table like: column1 column2 column3 column4 A B C D wants to convert it as: Column A B C D Without using this union all in oracle: select column1 as Column from dual union all select column2 as Column from dual union all select column3 as Column from dual union all select column4 as Column from dual 回答1: You can try to use unpivot select v from ( SELECT 'A' column1,'B' column2,'C' column3,'D' column4 from dual ) t unpivot ( v for val in (column1,column2,column3,column4) ) u;

问题 So, I previously asked this question: Can someone help me compare using F# over C# in this specific example (IP Address expressions)? I was looking at the posted code and I was wondering if this code could be written without it producing a warning: let [|a;b;c;d|] = s.Split [|'.'|] IP(parseOrParts a, parseOrParts b, parseOrParts c, parseOrParts d) Is it possible to do something for the match _ pattern ot ignore? Without adding in something like Active Patterns? i want to keep the code as

问题 I am trying to do some image analysis using an Inverse Perspective Map. I used the openCV functions getTransform and findHomography to generate a transformation matrix and apply it to the source image. This works well and I am able to get the points from the image I want. The problem is, I don't know how I can take individual point values and undo the transform to draw them back on the original picture. I want to only undo the transform for this set of points to find their original location.

问题 When i'm outputting some of my double variables they're being written in exponential form using fwrite. Can i set some defaults in PHP where whenever a variable is displayed (copied or stored) it always happens in decimal format? To be precise the problem occurs when i use the json_decode method on a json string which contains a double value (which is not in exponential form). That double value after converting an an object becomes exponential. 回答1: Assuming the numbers are still floats when

问题 I am going to be translating an XML document into another XML document based on an eXtensible Style Language Transformation. Where can I find good tutorials about how to do this in .NET? I have found some stuff about how to do it using open source tools. But what about the .NET framework? Just a couple of other quick questions... Could somebody please give me a quick and dirty explanation of the XSLT order of operations? I am still a little confused about what happens? Are there any explicit

问题 We have multiple versions of our web services (both REST and SOAP) in production, and the number keeps getting bigger with every release. Between versions, there can be minor changes (usually additions of new fields) to requests and responses. If we were to retire old versions, how could we continue to service requests for old versions? One aspect of a possible solution involves creating "virtual endpoints" to route requests for previous versions to the new versions of the same services. Thus

问题 Edit 6 - Complete re-write in relation to comments/ongoing research Edit 7 - Added projection / view matrix..... As I'm not getting far with this, I added view/projection matrix from the Google demo - please see code below: If anyone can point out where I'm going wrong it really would be appreciated, as I'm still getting a blank screen when I put ""gl_position = a_position * uMVPMatrix;" + into my vertex shader (with "gl_position = a_position;" + my quad is displayed at least.......) Declared

问题 With a camera inside a cylinder I capture a image. I want to transform that image into a plane 2d. The image inside the cylinder have a lot of dots which forms a grid. What I tried to do was estimating the transformation. With blob analysis I can detect the center of each point and obtain the coordinates in pixels. I save this in matrix called ImCilynder. After that i create a matrix with coordinates of that points in the plane with the name Im2d. I calculate the transformation (H) solving