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Showing posts with the label Programming and the Web for Beginners

http://www.dukelearntoprogram.com/course1/example/index.php

By Urban Picasso -
// write your code here //Function returns chopped pixel color values function pixchange(pixval){     var x = Math.floor(pixval/4) * 4;     return x; } //Code section chops bits of pixel colors of image that hides another image function chop2hide(image){     for(var px of image.values()){         px.setRed(pixchange(px.getRed()));         px.setGreen(pixchange(px.getGreen()));         px.setBlue(pixchange(px.getBlue()));     }     return image; } //Code Section used to shift bits of pixel colors of image to be hidden function shift(im){   var nim = new SimpleImage(im.getWidth(),im.getHeight());   for(var px of im.values()){     var x = px.getX();     var y = px.getY();     var npx = nim.getPixel(x,y);     npx.setRed(Math.floor(px.getRed()/64));     npx.setGreen(Math.floor(px.getGreen()/64)); ...
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By Urban Picasso -
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<p>The following picture was given with a hidden message to extract:</p> <center><img src = "http://i36.photobucket.com/albums/e42/Samksha/hiltonHiding2bitMessage_zpsze7d7x8e.png" /></center> <p>After extraction, this is what the hidden message was!</p> <center><img src = "http://i36.photobucket.com/albums/e42/Samksha/Part%203_zpsmdhehkly.png"/></center> <h3> Algorithm</h3> <p> The algorithm used for the extraction is similar to the one used for extraction in the first part.</p> <h3> Code</h3> <pre> function pchange(pixval) {     var x = (pixval-Math.floor(pixval/4)*4)*64;     return x; } function extract(image) {     for(var pixel of image.values())     {         pixel.setRed(pchange(pixel.getRed()));         pixel.setGreen(pchange(pixel.getGreen()));        ...
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nice one

By Urban Picasso -
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 Steganography Original Images This is the image that will be used to hide the second image! And this is the image that will be hidden in the first image! Sources for the images: https://www.hdwallpapers.net/abstract/colorful-diamond-wallpaper-674.htm https://www.hdwallpapers.net/abstract/dark-wood-texture-wallpaper-383.htm After the Hiding This is what the image looks like with the hidden value: And this is what the hidden image looks like after it is extracted: Algorithm The algorithm used to hide an image inside another using 2 bits is quite similar to the 4 bits, but has some distinctive differences. Instead of using 2^4, or 16, as the number used for dividing, we will be using 2^2, or 4. The first two bits of the image to be hidden are selected using the shift function. Since it's a 2 bit hidden message, we take the two most significant bits of the image we are hiding, i.e., "Diamond.jpg", by dividing the pixel value...
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Hide And Extract Image 2 bits

By Urban Picasso -
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//Function returns chopped pixel color values function pixchange(pixval){     var x = Math.floor(pixval/4) * 4;     return x; } //Code section chops bits of pixel colors of image that hides another image function chop2hide(image){     for(var px of image.values()){         px.setRed(pixchange(px.getRed()));         px.setGreen(pixchange(px.getGreen()));         px.setBlue(pixchange(px.getBlue()));     }     return image; } //Code Section used to shift bits of pixel colors of image to be hidden function shift(im){   var nim = new SimpleImage(im.getWidth(),im.getHeight());   for(var px of im.values()){     var x = px.getX();     var y = px.getY();     var npx = nim.getPixel(x,y);     npx.setRed(Math.floor(px.getRed()/64));     npx.setGreen(Math.floor(px.getGreen()/64));     np...
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Modify Image Algorithmically

By Urban Picasso -
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function ensureInImage(coordinate, size){     //coordinate cannot be negative     if (coordinate < 0){         return 0;     }     //coordinate size must be between [0....size-1]     if (coordinate >= size){         return size-1;     }     else{         return coordinate;     }   } function getPixelNearby(image , x, y, diameter){     var dx = Math.random() * diameter - diameter/2;     var dy = Math.random() * diameter - diameter/2;     var nx = ensureInImage(x + dx, image.getWidth());     var ny = ensureInImage(y + dy, image.getHeight());     return image.getPixel(nx, ny); } //Select An Image from the list var image = new SimpleImage ("chapel.png"); //I'm gonna create a new image that is the same size as my starting image. var output = new SimpleImage(image.get...
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Creating a Image Algorithmic-ally

By Urban Picasso -
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function dist(pixel,x,y){     var dx = pixel.getX() - x ;     var dy = pixel.getY() - y ;     return Math.sqrt(dx * dx + dy * dy); } // start with a blank image var output = new SimpleImage(320,320); // write something here for (var pixel of output.values()){     if (dist(pixel,100,100) < 50 ){         pixel.setRed(255 - 4 * dist (pixel,100,100));     }     else if (dist(pixel,200,200) < 80 ){         pixel.setGreen(255 - 4 * dist (pixel,200,200));     }               else if (Math.random() > 0.995 ){         pixel.setRed(255);         pixel.setGreen(255);     }     pixel.setBlue(Math.max(1.05 * pixel.getY() - pixel.getX() ,  pixel.getX() - 1.5 * pixel.getY() )) } print (output); OR //all the points here are numbered in the same wa...
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QUIZ Steganography Extraction and Duplication solutions

By Urban Picasso -
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Suppose we decide to write a function to set the color of a pixel by giving it three RGB values. Think about what the parameters and the code would need to be for this function. Let’s call the function setColor. Which one of the following is a correct setColor function?

By Urban Picasso -
// write your code here function clearbits(colorval){     //compute the same color value with the lowest bits zeroed     var x = Math.floor(colorval/16)*16;     return x; } function setColor( r, g, b) {     for (var pixel of start.values()){         pixel.setRed(r);      pixel.setGreen(g);    pixel.setBlue(b);     } return start; } function chop2hide(image){     //for each pixel in the image     for (var px of image.values()){         //clear the lower values of red         px.setRed(clearbits(px.getRed()));         //clear the lower values of green         px.setGreen(clearbits(px.getGreen()));         //clear the lower values of blue         px.setBlue(clearbits(px.getBlue()));     }     return image; } ...
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EXTRACTION OF IMAGE code

By Urban Picasso -
// write your code here function clearbits(colorval){     //compute the same color value with the lowest bits zeroed     var x = Math.floor(colorval/16)*16;     return x; } function chop2hide(image){     //for each pixel in the image     for (var px of image.values()){         //clear the lower values of red         px.setRed(clearbits(px.getRed()));         //clear the lower values of green         px.setGreen(clearbits(px.getGreen()));         //clear the lower values of blue         px.setBlue(clearbits(px.getBlue()));     }     return image; } function shift(image){     //for each pixel in an image     for (var px of image.values()){         //shift the red bits over         px.setRed(px.getRed()/16);   ...
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doubling image size

By Urban Picasso -
// write your code here //selecting the image i wanted to enlarge var smallImage = ("smalllion.jpg"); //creating a blank image which is having twice as size of original image var bigImage =   ("smallImage.getWidth() *2 , smallImage.getHeight() *2"); for (var px of bigImage.values()){     var x = px.getX();     var y = px.getY();     var calx = Math.floor(x/2);     var caly = Math.floor(y/2);     var smallPixel = smallImage.getPixel(calx,caly);     px.setRed(smallPixel.getRed());     px.setGreen(smallPixel.getGreen());     px.setBlue(smallPixel.getBlue()); } print (bigImage);
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Select two images to use. You will hide one image in another image. They most likely will be different sizes and in the next step we will crop both of them to be the same size. In order to hide one image inside of another image, the images need to be the exact same size. Write the function crop(image, width, height) that has three parameters: image is a complete image, and width and height are numbers. This function creates and returns a new image from the parameter image, with the new image having the width and height of the specified width and height parameters, thus cropping the picture by ignoring the pixels on the right side or bottom that are beyond the specified width or height of the picture.

By Urban Picasso -
function clearbits(colorval){     //compute the same color value with the lowest bits zeroed     var x = Math.floor(colorval/16)*16;     return x; } function chop2hide(image){     //for each pixel in the image     for (var px of image.values()){         //clear the lower values of red         px.setRed(clearbits(px.getRed()));         //clear the lower values of green         px.setGreen(clearbits(px.getGreen()));         //clear the lower values of blue         px.setBlue(clearbits(px.getBlue()));     }     return image; } function shift(image){     //for each pixel in an image     for (var px of image.values()){         //shift the red bits over         px.setRed(px.getRed()/16);         //shift t...
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By Urban Picasso -
function setBlack(pixel) {      pixel.setRed(0);      pixel.setGreen(0);      pixel.setBlue(0);      return pixel; } function pixelOnEdgeDifferentThicknesses (pixel, image, vWidth, hWidth) {      var x = pixel.getX();      var y = pixel.getY();      if (x < vWidth) return true;      if (y < hWidth) return true;      if (x >= image.getWidth() - vWidth) return true;      if (y >= image.getHeight() - hWidth) return true;      return false; } var image = new SimpleImage("usain.jpg"); for (var pixel of image.values()) {      if (pixelOnEdgeDifferentThicknesses (pixel, image, 10, 40)) {                 pixel = setBlack(pixel);      } } print(image);
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Consider the following program from the lesson, shown below with missing code to add a border of 30 to the image. Consider the following sections of code that call the pixelOnEdge function in different ways. Select the three of them that will still run correctly and put a border of 30 around the image.

By Urban Picasso -
function setBlack(pixel) {      pixel.setRed(0);      pixel.setGreen(0);      pixel.setBlue(0);      return pixel; } function pixelOnEdge (pixel, image, borderWidth) {      var x = pixel.getX();      var y = pixel.getY();      if (x < borderWidth) return true;      if (y < borderWidth) return true;      if (x >= image.getWidth() - borderWidth) return true;      if (y >= image.getHeight() - borderWidth) return true;      return false; } var image = new SimpleImage("usain.jpg"); for (var pixel of image.values()) {     if (pixelOnEdge(pixel, image, 30)) {       pixel = setBlack(pixel);      } } print(image); OR function setBlack(pixel) {      pixel.setRed(0);      pixel.setGreen(0);     ...
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The function moreRed should increase the color of the red value of a pixel by a specified amount so that after executing the code which calls this function (shown below) then the picture is more red by adding 100 to each pixel’s red value.

By Urban Picasso -
Which one of the following is the correct implementation of moreRed ? // write your code here function moreRed(pixel, amount) {      var r = pixel.getRed() + amount;      if (r > 255)  r = 255;      pixel.setRed(r);      return pixel; } var image = new SimpleImage ("eastereggs.jpg"); print (image); for ( var pixel of image.values()){     if (moreRed(pixel, 200) ){             }     } print (image);
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The function swapRedGreen has one parameter, a pixel. This function swaps the red and green values and returns the resulting red, green and blue values somehow. Which one of the following is the correct code for this function?

By Urban Picasso -
// write your code here function swapRedGreen(pixel) {      var newGreen = pixel.getRed();      var newRed = pixel.getGreen();      pixel.setGreen(newGreen);      pixel.setRed(newRed);      return pixel; } var image = new SimpleImage ("eastereggs.jpg"); print (image); for ( var pixel of image.values()){     if (swapRedGreen(pixel) ){             }     } print (image);
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Now modify the program one more time to replace the two functions pixelOnVerticalEdge and pixelOnHorizontalEdge with one function to do the same thing called pixelOnEdgeDifferentThicknesses( ). The parameters are not shown. You should decide on the parameters. Write the function and test it to make sure it works the same as the two functions it replaces, so you can generate pictures with borders that have different thicknesses for the vertical borders vs. the horizontal borders. Here is an example: Here is an island picture:

By Urban Picasso -
Image
// write your code here function setBlack(pixel){     pixel.setBlue(0);     pixel.setGreen(0);     pixel.setRed(0);     return pixel; } function pixelOnEdgeDifferentThicknesses(pixel, image, borderWidth){     var x = pixel.getX();     var y = pixel.getY();       if (x < borderWidth) return true;     if (y < (borderWidth+40)) return true;     if (x >= image.getWidth() - borderWidth) return true;     if (y >= image.getHeight() - (borderWidth+40)) return true;     return false; } var image = new SimpleImage ("lion.jpg"); print (image); for ( var pixel of image.values()){     if (pixelOnEdgeDifferentThicknesses(pixel, image, 25) ){         pixel = setBlack(pixel);     }     } print (image); Here is the island picture with a border around it: Here is a picture of the island with differe...
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Now modify the border program to specify two thicknesses, one for the vertical borders and one for the horizontal borders. You should write the two boolean functions shown below. Be sure to print the image and run your program with different border values for the horizontal and vertical edges. a) function pixelOnVerticalEdge(pixel, image, borderWidth)—This function has three parameters where pixel is a single pixel, image is the complete image, and borderWidth is an integer specifying the thickness of the vertical borders. This function returns true if the pixel’s location is within borderWidth of any of the two vertical borders, and thus on the border. Otherwise it returns false. b) function pixelOnHorizontalEdge(pixel, image, borderWidth)—This function has three parameters where pixel is a single pixel, image is the complete image, and borderWidth is an integer specifying the thickness of the horizontal borders. This function returns true if the pixel’s location is within borderWidth of any of the two horizontal borders, and thus on the border. Otherwise it returns false.

By Urban Picasso -
Image
// write your code here function setBlack(pixel){     pixel.setBlue(0);     pixel.setGreen(0);     pixel.setRed(0);     return pixel; } function pixelOnVerticalEdge(pixel, image, borderWidth){     var x = pixel.getX();     var y = pixel.getY();       if (x < borderWidth) return true;         if (x >= image.getWidth() - borderWidth) return true;     return false; } function pixelOnHorizontalEdge(pixel, image, borderWidth){     var x = pixel.getX();     var y = pixel.getY();     if (y < borderWidth) return true;         if (y >= image.getHeight() - borderWidth) return true;         return false; } var image = new SimpleImage ("lion.jpg"); print (image); for ( var pixel of image.values()){     if (pixelOnHorizontalEdge(pixel, image, 25) ){      ...
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Write the complete JavaScript program to put the border around a picture, and include the following functions that are included from the lesson. You should be able to write these functions without looking at the code from the lesson. Be sure to print the image so you can see it and run the program with different border values. a) function setBlack(pixel) - This function has a parameter pixel that represents a single pixel, and returns a pixel that has been changed to be the color black. b) function pixelOnEdge(pixel, image, borderWidth) - This function has three parameters where pixel is a single pixel, image is the complete image, and borderWidth is an integer specifying the thickness of the borders. This function returns true if the pixel’s location is within borderWidth of any of the four borders, and thus on the border. Otherwise it returns false.

By Urban Picasso -
// write your code here function setBlack(pixel){     pixel.setBlue(0);     pixel.setGreen(0);     pixel.setRed(0);     return pixel; } function pixelOnEdge(pixel,image,borderWidth){     var x = pixel.getX();     var y = pixel.getY();     if (x < borderWidth) return true;     if (y < borderWidth) return true;     if (x >= image.getWidth() - borderWidth) return true;     if (y >= image.getHeight() - borderWidth) return true;     return false; } var image = new SimpleImage ("lion.jpg"); print (image); for ( var pixel of image.values()){     if (pixelOnEdge(pixel,image,10)){         pixel = setBlack(pixel);     } } print (image);
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Write a JavaScript program that has a function named swapRedGreen with one parameter pixel. This function should swap the red and green values of the pixel. Pick an image, print the image, then apply swapRedGreen to every pixel in the image, and print the new image. The choice of your image is important. For some images you may not notice any change. Think about what type of image you should use for testing your function.

By Urban Picasso -
Image
// write your code here function swapRedGreen(pixel){     G = pixel.getGreen();     R = pixel.getRed();     if (G >= 200 ){         pixel.setRed(255);         pixel.setGreen(0);         return true     }     if (R >= 200){         pixel.setRed(0);         pixel.setGreen(255);         return true;     } } var image = new SimpleImage("smallhands.png"); print (image); for (pixel of image.values()){     pixel = swapRedGreen(pixel); } print (image);
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week 3 - Design Principles for Programming Final Quiz solutions

By Urban Picasso -
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