I am trying to create jigsaw puzzle shapes using P5.js. After creating puzzle shapes, I want to cut areas from main image into pieces. For that I have options of using GET() or COPY():
But both of them take fix height and width as parameter. How can I copy a custom area like given in following shapes:
https://editor.p5js.org/techty/sketches/h7qwatZRb
let cutout = createGraphics(w, h);
cutout.background(255, 255);
cutout.blendMode(REMOVE);
//draw shape on cutout
let newshapeimagegraphic = createGraphics(w, h);
newshapeimagegraphic.image(myImg, 0, 0);
newshapeimagegraphic.blendMode(REMOVE);
newshapeimagegraphic.image(cutout, 0, 0);
image(newshapeimagegraphic, 0, 0);
Related
Curently based on Sascha Willems examples I've cerated samplerCube texture for fragment shader.
It has same JPG image copied to all 6 layers (faces).
I use stbi image library for image loading, it works okay if I use it for regular 2D texture, but if it's mapped on cube mesh it creates distorted image:
int width = 0, height = 0, channel = 0;
float* pixels = stbi_loadf("textures/test.hdr", &width, &height, &channel, STBI_rgb_alpha);
if(!pixels) throw std::runtime_error("failed to load texture image!");
this->texture_image.create_image(width, height, VK_FORMAT_R32G32B32A32_SFLOAT, VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT);
this->texture_image.fill_memory(width, height, 4*sizeof(float), pixels);
this->texture_image.create_image_view(VK_FORMAT_R32G32B32A32_SFLOAT, VK_IMAGE_ASPECT_COLOR_BIT);
stbi_image_free(pixels);
Found how to do it here: https://learnopengl.com/PBR/IBL/Diffuse-irradiance
Even if it's in OpenGL the concenpt is the same.
I have a grayscale image that serves as a soft mask and I want to use it on a group of PDF objects (images or paths).
The mask and the objects do not necessarily use the same transformation matrix, and there might be more than one object to mask, so that excludes the possibility of using the SMask attribute of the ImageXObject dictionary.
So after reading some of the PDF specification, it looks like I should do the following: create a transparency group with the objects to mask, then draw it with the soft mask set on the graphics state.
Will that work? How can I achieve this, preferably with PDFBox?
Here's an example. I have these two images: the mask and another image.
The mask image is 200x200. It is drawn with the matrix [[4 0 100] [0 4 100]].
The image is 400x300. It is drawn with the matrix [[2 0 100] [0 2 150]].
Additionally, a 400x400 black square is drawn below the image with no transform matrix.
So a transparency group is created with the image and the square, then it's drawn with the mask image. Here's the expected result:
Rather ugly as far as the effect goes, but that's just an example.
As far as I can see establishing an extended graphics state soft mask is a very manual task in PDFBox. You can do so as follows:
try ( PDDocument document = new PDDocument() ) {
final PDImageXObject image = RETRIEVE PHOTO IMAGE;
final PDImageXObject mask = RETRIEVE MASK IMAGE;
PDTransparencyGroupAttributes transparencyGroupAttributes = new PDTransparencyGroupAttributes();
transparencyGroupAttributes.getCOSObject().setItem(COSName.CS, COSName.DEVICEGRAY);
PDTransparencyGroup transparencyGroup = new PDTransparencyGroup(document);
transparencyGroup.setBBox(PDRectangle.A4);
transparencyGroup.setResources(new PDResources());
transparencyGroup.getCOSObject().setItem(COSName.GROUP, transparencyGroupAttributes);
try ( PDFormContentStream canvas = new PDFormContentStream(transparencyGroup) ) {
canvas.drawImage(mask, new Matrix(400, 0, 0, 400, 100, 100));
}
COSDictionary softMaskDictionary = new COSDictionary();
softMaskDictionary.setItem(COSName.S, COSName.LUMINOSITY);
softMaskDictionary.setItem(COSName.G, transparencyGroup);
PDExtendedGraphicsState extendedGraphicsState = new PDExtendedGraphicsState();
extendedGraphicsState.getCOSObject().setItem(COSName.SMASK, softMaskDictionary);
PDPage page = new PDPage(PDRectangle.A4);
document.addPage(page);
try ( PDPageContentStream canvas = new PDPageContentStream(document, page) ) {
canvas.saveGraphicsState();
canvas.setGraphicsStateParameters(extendedGraphicsState);
canvas.setNonStrokingColor(Color.BLACK);
canvas.addRect(100, 100, 400, 400);
canvas.fill();
canvas.drawImage(image, new Matrix(400, 0, 0, 300, 100, 150));
canvas.restoreGraphicsState();
}
document.save(new File(RESULT_FOLDER, "SoftMaskedImageAndRectangle.pdf"));
}
The result:
If I were you, though, I would not use a bitmap image for the soft mask but instead a PDF gradient. The result most likely will be much less pixelated.
I am looking for a solution to intersection point of a cube and a line. So i used
GLES20.glReadPixels(touchX, touchY, 1, 1, GLES20.GL_DEPTH_COMPONENT, GLES20.GL_FLOAT, zz);
and i showed the zz , but result was 0. so how could i get the depth buffer value of a Cube when i touched on the cube(actually on the 2d screen). I use GLES20 and Android API level15.And My code is below.
ByteBuffer PixelBuffer = ByteBuffer.allocateDirect(4);
ByteBuffer zBuffer = ByteBuffer.allocateDirect(4);
PixelBuffer.order(ByteOrder.nativeOrder());
PixelBuffer.position(0);
zBuffer.order(ByteOrder.nativeOrder());
zBuffer.position(0);
FloatBuffer zz;
zz = zBuffer.asFloatBuffer();
GLES20.glReadPixels(touchX, touchY, 1, 1, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, PixelBuffer);
GLES20.glReadPixels(touchX, touchY, 1, 1, GLES20.GL_DEPTH_COMPONENT, GLES20.GL_FLOAT, zz);
by the way picking color works fine.
Thanks!
You forget to prepare target framebuffer to read... Try like this:
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glPixelStorei(GL_PACK_ALIGNMENT, 1);
glReadPixels(0, 0, deviceWidth, deviceHeight, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
Or just write simple shader and render your zbuffer data into your FBO, simething like
gl_FragColor = vec4(vec3(gl_FragCoord.z), 1.0);
and then read color information form this FBO...
I am trying to learn how to do OpenGL using OpenTK and I can successfully draw polygons, circles, and triangles so far but my next question is how to draw text? I have looked at the example on their homepage which was in C# and I translated it to VB .NET.
It currently just draws a white rectangle so I was hoping that someone could spot an error in my code or suggest another way to draw text. I will just list my paint event.
Paint event:
GL.Clear(ClearBufferMask.ColorBufferBit)
GL.Clear(ClearBufferMask.DepthBufferBit)
Dim text_bmp As Bitmap
Dim text_texture As Integer
text_bmp = New Bitmap(ClientSize.Width, ClientSize.Height)
text_texture = GL.GenTexture()
GL.BindTexture(TextureTarget.Texture2D, text_texture)
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, All.Linear)
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, All.Linear)
GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, text_bmp.Width, text_bmp.Height, 0 _
, PixelFormat.Bgra, PixelType.UnsignedByte, IntPtr.Zero)
Dim gfx As Graphics
gfx = Graphics.FromImage(text_bmp)
gfx.DrawString("TEST", Me.Font, Brushes.Red, 0, 0)
Dim data As Imaging.BitmapData
data = text_bmp.LockBits(New Rectangle(0, 0, text_bmp.Width, text_bmp.Height), Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb)
GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, Width, Height, 0, PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0)
text_bmp.UnlockBits(data)
GL.MatrixMode(MatrixMode.Projection)
GL.LoadIdentity()
GL.Ortho(0, width, Height, 0, -1, 1)
GL.Enable(EnableCap.Texture2D)
GL.Enable(EnableCap.Blend)
GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.OneMinusSrcAlpha)
GL.Begin(BeginMode.Quads)
GL.TexCoord2(0.0F, 1.0F)
GL.Vertex2(0.0F, 0.0F)
GL.TexCoord2(1.0F, 1.0F)
GL.Vertex2(1.0F, 0.0F)
GL.TexCoord2(1.0F, 0.0F)
GL.Vertex2(1.0F, 1.0F)
GL.TexCoord2(0.0F, 0.0F)
GL.Vertex2(0.0F, 1.0F)
GL.End()
GlControl1.SwapBuffers()
You'll get a white rectangle if your card doesn't support NPOT (non-power-of-two) texture sizes. Try testing by setting the bitmap size to e.g. 256x256.
That is an ok method. If you plan to draw lots of text or even a medium amount, that will absolutely destroy performance. What you want to do is look into a program called BMFont:
www.angelcode.com/products/bmfont/
What this does is create a texture atlas of text, along with an xml file with the positions, width and height and offsets of every letter. You start off by reading that xml file, and loading each character into a class, with the various values. Then you simply make a function that you pass a string which binds the atlas, than depending on the letters in the string, draws a quad with texture coordinates that vary on the xml data. So you might make a:
for each _char in string
create quad according to xml size
assign texture coordinates relative to xml position
increase position so letters don't draw on top of each other
There are tutorials in other languages on the BMFont website which can be helpful.
I am currently embedding an image into an exported SVG document and am running into an issue with the transformation matrix on a UIView that I am scaling and moving.
My output currently pushes the matrix into the attribute transform
transform="matrix(view.transform.a, view.transform.b, view.transform.c, view.transform.d, view.transform.tx, view.transform.ty)"
This all works perfectly fine with the exception of the tx and ty values of the transformation. For some reason when I scale the view these values start getting weird , and I'm not sure what is going on. Obviously core graphics is handeling the matrix a little different than svg is, but does anyone know what the difference is?
It looks like CoreGraphics sets up the transform so that the vector is in the center of the view while in SVG the vector would be at top left of the image.
Multiplying the transform solved this for me:
// create an offset matrix<br />
CGAffineTransform offset1 = CGAffineTransformMake(1, 0, 0, 1, -originalViewWidth/2, -originalViewHeight/2);
CGAffineTransform offset2 = CGAffineTransformMake(1, 0, 0, 1, originalViewWidth/2, originalViewHeight/2);
CGAffineTransform matrix = CGAffineTransformConcat(offset1, view.transform);
matrix = CGAffineTransformConcat(matrix, offset2);