graphics

问题 I would like to rotate a rectangle around its center point and it should remain in the place that it is supposed be drawn and rotate in that space this is my code: AffineTransform transform = new AffineTransform(); transform.rotate(Math.toRadians(45),rectangle.width/2, rectangle.height/2); Shape transformed = transform.createTransformedShape(rectangle); g2.fill(transformed) the rectangle is rotated but it is drawn at a different part of the screen, how can I correct this? 回答1: I haven't tried

问题 The OpenGL SuperBible discusses texture buffer objects, which are textures formed from data inside VBOs. It looks like there are benefits to using them, but all the examples I've found create regular textures. Does anyone have any advice regarding when to use one over the other? 回答1: According to the extension registry, texture buffers are only 1-dimensional, cannot do any filtering and have to be accessed by accessing explicit texels (by index), instead of normalized [0,1] floating point

问题 I'm working on a tablet app. I tried to set high-resolution (2223x3553) images as background using Layout.setBackgroundResource(ResId) . The app crashed while testing on Nexus 7 , I won't paste the stack traces since there were like 8 or 9 exceptions with about 300 red lines in the LogCat and it took me a while to figure out the reason. I got it after I noticed the OutOfMemoryException , using 1280x800 images the app runs fine but some quality loss has occurred since those images are designed

问题 I'm looking for a fast, accurate implementation of RGB to HSB and HSB to RGB in pure C. Note that I'm specifically looking for Hue, Saturation, Brightness and not HSL (Luminosity). Of course I have Googled this extensively, but speed is of the utmost importance here and I am looking for any specific recommendations for solid, fast, reliable code. 回答1: First off HSB and HLS were developed to specify numerical Hue, Saturation and Brightness (or Hue, Lightness and Saturation) in an age when

问题 Is there any way to bend a BufferedImage in Java? I thought that if I crop the image into smaller pieces and rotate them then I would essentially bend the image, but it doesn't seem to work. Here is the method I created: /** * This is a recursive method that will accept an image the point where the bending will start and the point where the bending will end, as well as the angle of bending * * @param original:the original image * @param startingPoint: the point where the bending should start

问题 I'm learning about framebuffers right now and I just don't understand what the Color attachment does. I understand framebuffers. What is the point of the second parameter in: glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureColorBuffer, 0); Why doesn't anything draw to my frame buffer when I change it to COLOR_ATTACHMENT1? How could I draw to the frame buffer by setting the texture to Color attachment 1? Why would using multiple color attachments be useful?

问题 I am having problem with the task of storing CGGradientRef in NSMutableArray. What do I have to wrapp it in to store it in the array and what to unwrap it. Thanks. 回答1: You don't have to wrap it in anything. Just cast it to id and add it to the array. You can do this for any CoreFoundation type derived from CFType (loosely anything ending in "Ref"). Alternatively, you can cast the NSMutableArray* to a CFMutableArrayRef and call CFArrayAppendValue(). This is no more typesafe; it calls the

问题 I often prefer to use a light text on dark background colortheme in IDEs. When I plot something in R the default colorscheme for plots is black text/borders/points on white background. I was trying to change this by default, preferably for specific devices called from R by default ( X11cairo , RStudioGD ), while keeping the normal defaults for 'output' devices such as pdf and png . My question is twofold: (1) How can I set default graphical parameters? and (2) Can I do this only for

问题 Consider the following d = data.frame(y=rnorm(120), x=rep(c("bar", "long category name", "foo"), each=40)) ggplot(d,aes(x=x,y=y)) + geom_boxplot() + theme(axis.text.x=element_text(size=15, angle=90)) The x-axis labels are aligned by the center of the label. Is it possible to automatically align on the right so that every label would end right below the graph? 回答1: This is precisely what the hjust and vjust parameters are for in ggplot . They control the horizontal and vertical justification

问题 Consider the following d = data.frame(y=rnorm(120), x=rep(c("bar", "long category name", "foo"), each=40)) ggplot(d,aes(x=x,y=y)) + geom_boxplot() + theme(axis.text.x=element_text(size=15, angle=90)) The x-axis labels are aligned by the center of the label. Is it possible to automatically align on the right so that every label would end right below the graph? 回答1: This is precisely what the hjust and vjust parameters are for in ggplot . They control the horizontal and vertical justification