Differences

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--- ch02-getting-going.html [2017/08/13 16:20]
mithat [The console]
+++ ch02-getting-going.html [2017/08/20 18:35] (current)
mithat [The console]
@@ Line 21: / Line 21: @@
 </file>
-This is an example of a program written in what Processing calls its Basic Mode. In Basic Mode, the program's execution will begin at the first statement in the source code file. It will then continue statement-by-statement until it reaches the end of the file.
+This is an example of a program written in what Processing calls its //Basic Mode//. In Basic Mode, the program's execution will begin at the first statement in the source code file. It will then continue statement-by-statement until it reaches the end of the file.
 Here's a program with two statements:
@@ Line 34: / Line 34: @@
 === Processing with an entry point ===
-Processing will automatically switch to Continuous Mode when you define at least one function in your program. (This is why you are not allowed to define functions in Basic Mode.) In Continuous Mode, Processing will look for a definition of a function called **''%%setup%%''**, and it will use this function as the point where the programs execution begins. Below is the Continuous Mode equivalent of the Basic Mode example above.
+Processing will automatically switch to //Continuous Mode// when you define at least one function in your program. (This is why you are not allowed to define functions in Basic Mode.) In Continuous Mode, Processing will look for a definition of a function called **''%%setup%%''**, and it will use this function as the point where the program's execution begins. Below is the Continuous Mode equivalent of the Basic Mode example above.
 <file java cranberries_continuous_mode.pde>
@@ Line 91: / Line 91: @@
 If a statement is the programming equivalent of a sentence, why are semicolons used to mark the end of statements rather than periods?
-The biggest reason for this is that the language on which Processing is based, Java, uses semicolons to mark the end of statements. But why does Java do this? Because the language on which a lot of Java syntax is based, C++, also uses semicolons. Why does C++ do this? Because ... , you get the idea.
+The biggest reason for this is that the language of the platform in which Processing is built, Java, uses semicolons to mark the end of statements. But why does Java do this? Because the language on which a lot of Java syntax is based, C++, also uses semicolons. Why does C++ do this? Because ... , you get the idea.
 The language ALGOL, whose development began in the late 1950's, may have been the first language to use the semicolon as the statement terminator. While the semicolon is widely used for this purpose, you should note that this is by no means universal.
@@ Line 105: / Line 105: @@
 ==== Comments ====
-FIXME Program statements and other things written a programming language are well-suited for getting your program to do what you want. That's their whole purpose! And if you write your programs using good style, which we hope you'll learn how to do throughout this book, your programs should be relatively straight-forward for someone with a decent knowledge of the programming language to understand.
+Program statements and other things written a programming language are well-suited for getting your program to do what you want. That's their whole purpose! And if you write your programs using good style, which we hope you'll learn how to do throughout this book, your programs should be relatively straight-forward for someone with a decent knowledge of the programming language to understand.
-However, there will be times when you will want to include text in your code to help human readers. For example, you might want to include some information about who authored the program, when it was written, licensing information, etc. That is what **comments** are for.
+However, there will be times when you will want to include text in your code just to help human readers. For example, you might want to include some information about who authored the program, when it was written, licensing information, etc. That is what **comments** are for.
-TODO
+There are three ways to write comments in Processing: the "standard" comment, the multi line comment, and the doc comment.
+=== "standard" comments ===
+The most common syntax for creating comments in Processing is to use a double forward slash: ''%%//%%''. Anything that comes after a double slash up to the end of the line is a comment and will be ignored by the Processing compiler. Here a version of the ''cranberries2.pde'' program with some added some comments to identify the author and other information and explain some of the code:
+<file java cranberries2-with-comments.pde>
+// The Most Spectacular Program Ever
+// Mithat Konar
+// Aug 19, 2017
+void setup() {
+  // advise the user about nutrition:
+  println("Cranberries are high in antioxidants.");
+  println("Chickpeas are high in tryptophan.");
+  println("Tomatoes are high in lycopene.");
+  println("OK?");  // confirm with the user.
+}
+</file>
+This comment type also sometimes called the single line comment.
+=== multiline comment ===
+The limitation with the "standard" comment above is that its awkward to use it to write a comment that should cover many lines.
+<code java>
+// A really awesome program
+// by Sora Antimony
+// Creates a pretty picture with lots of
+// unicorns and rainbows. The unicorns
+// dance.
+</code>
+For situations like this, the multiline comment is often a better option. A multiline comment starts with ''/*'' and ends with ''*/'' --- even if the closing ''*/'' is several lines down.
+<code java>
+/* A really awesome program
+by Sora Antimony
+Creates a pretty picture with lots of
+unicorns and rainbows. The unicorns
+dance. */
+</code>
+A bit of formatting can make it pretty:
+<code java>
+/* A really awesome program
+   by Sora Antimony
+   Creates a pretty picture with lots of
+   unicorns and rainbows. The unicorns
+   dance.
+*/
+</code>
+or
+<code java>
+/*
+ * A really awesome program
+ * by Sora Antimony
+ * Creates a pretty picture with lots of
+ * unicorns and rainbows. The unicorns
+ * dance.
+*/
+</code>
+=== doc comment ===
+The doc comment is a special case of the multiline comment. It's short for "documentation comment." Its rules and behavior are identical to the multiline comment with one important difference: There is a tool available to Java programs (the platform on which Processing is based) called ''javadoc'' that when applied to a source file will find all the doc comments and produce nicely formatted and pretty documentation from them.
+To turn a mutiline comment into a doc comment, just add an additional ''*'' in the opening tag:
+<code java>
+/* I'm a multiline comment, even though I really only take up one line. */
+/** I'm a doc comment. I'm so special that the
+    javadoc tool will read me and extract my
+    precious info. */
+</code>
+We won't go any deeper into the when and why of doc comments as it's a bit of an advanced subject. But it's important to mention them here as you will probably see other people's code that uses them.
 ===== Program output =====
@@ Line 122: / Line 201: @@
 ))
-In Processing, there is a console built into the IDE that you can use however you want. It is the dark box toward the bottom of the window (Figure TODO). Thus, when you run a Processing program from the Processing IDE, you will be able to see and use the console without having to do any extra work.
+There is a console built into the Processing IDE should you want to use it. It's the dark box toward the bottom of the window. If it ever becomes hidden, you can activate it by clicking on the "Console" tab. This means when you run a Processing program from the Processing IDE, you will be able to see and use the console without having to do any extra work.
 === Outputting text ===
@@ Line 229: / Line 308: @@
 Because text-based input is as involved as it is in Processing, we will avoid it in this text. We will, however, work with some of the interaction features that Processing makes very easy when we cover //event handling//.
 </WRAP>
 ==== The canvas ====
-The console in Processing is typically used for printing out diagnostic and similar information; rarely is it used as the primary form of output. Most people who use Processing use the **canvas** for this. The canvas is where Processing draws its graphics.((The term //console// is a standard term in computing; the term //canvas// isn't quite so.
+The console in Processing is typically used for printing out diagnostic and similar information; rarely is it used as the primary form of output. Most people who use Processing use do so because they want graphical output. Processing uses its **canvas** for this.((The term //console// is a standard term in computing; the term //canvas// isn't quite so.
 ))
-TODO: coordinate system
+{{::empty-canvas.png?nolink|Empty canvas}}
+You will recognize the canvas as the inner box that's inside the window that has been popping up when you've been working with console output.
+=== Coordinate system ===
+The Processing canvas consists of a two-dimensional space that is addressed using x and y coordinates. The origin of the canvas (0, 0) is in the upper left corner. A positive x value moves the referenced point to the right, and positive y values move the point down.
 === Rectangles ===
+You can draw rectangles on the canvas with the ''%%rect%%'' function.
 The ''%%rect%%'' function is an example of a function that accepts multiple **parameters** or **arguments**---values that are passed into a function for it to use. In Processing, parameters are placed inside the parenthesis of a function call and if there is more than one parameter, they must be separated with commas.
-The ''%%rect%%'' function takes four parameters: the first two specify where to draw it; that is, the x and y coordinates of the upper left corner within the canvas.((You can change the meaning if the first two arguments by using the ''%%rectMode()%%'' function.
+The ''%%rect%%'' function takes four parameters: the first two specify where to draw it; that is, the x and y coordinates of the upper left corner on the canvas. The next two specify the size as width and height in pixels.((You can change the meaning if the first two arguments by using the ''%%rectMode()%%'' function.
-)) The next two specify the size as width and height in pixels.
+))
-The following code will draw a rectangle whose upper left corner is at the upper left corner of the canvas. The rectangle will be 40 pixels wide and 20 pixels high.
+The following code will draw a rectangle whose upper left corner is in the upper left corner of the canvas. The rectangle will be 40 pixels wide and 20 pixels high.
 <code java>
@@ Line 284: / Line 368: @@
 }
 </code>
+{{::three-rectangles.png?nolink|Three rectangles}}
 We have used integers only as parameters above. However, Processing will also accept floating-point numbers (e.g., ''%%16.67%%'') for any of the parameter values as well.
@@ Line 312: / Line 399: @@
 }
 </code>
-To draw more than one rectangle, just make more than one call to the ''%%ellipse%%'' function. They will be drawn in the order you write them.
+To draw more than one ellipse, just make more than one call to the ''%%ellipse%%'' function. They will be drawn in the order you write them.
 <code java>
@@ Line 330: / Line 417: @@
 }
 </code>
+{{::three-ellipses.png?nolink|Three ellipses}}
 Again, parameter values may be integers of floating-point numbers.
 === Lines ===
-TODO
+To draw lines, you can use, you Processing's, guessed it, ''%%line%%'' function. The ''%%line%%'' function has four parameters: starting x coordinate, starting y coordinate, ending x coordinate, ending y coordinate.((You can add and additional pair of coordinates for doing 3D stuff, but we won't be covering that here.))
+<code java>
+void setup() {
+  line(10, 10, 20, 40);
+  line(30, 10, 40, 40);
+  line(50, 10, 60, 40);
+  line(70, 10, 80, 40);
+}
+</code>
+{{::four-lines.png?nolink|Four lines}}
+As was the case for ''%%rectangle%%'' and ''%%ellipse%%'', the parameter values you provide to the ''%%line%%'' function can be floating point values as well.
 Processing provides a //lot// more control over what you can draw and how (including rendering images and graphic versions of text), but for the remainder of this text we will limit ourselves to the above elements.
@@ Line 349: / Line 452: @@
 void setup() {
   // set the background color using an RGB values
-  background(0, 0, 200);
+  background(64, 64, 128);
   // make the pen two pixels wide
   strokeWeight(2);
   // make the pen red color using RGB values
   stroke(255, 0, 0);
   // make shapes fill with a dark red color using RGB values
   fill(192, 0, 0);
   ellipse(30, 30, 50, 50);
   // make the pen red color using RGB values
   stroke(0, 255, 0);
   // make shapes fill with a dark green color using RGB values
   fill(0, 192, 0);
   ellipse(70, 70, 50, 50);
 }
 </code>
-In keeping with the spirit of this text being about programing concepts rather than the Processing language, we will not delve into this any further at this point. If you want to learn more, everything you need to know about these (and more!) is simply and concisely documented on the Processing reference Web pages (http:%%//%%processing.org/reference/) under the **Color** and **Attributes** headings.
+{{::color-example.png?nolink|Color example}}
+In keeping with the spirit of this text being about programming concepts rather than the Processing language, we will not delve into this any further at this point. If you want to learn more, everything you need to know about these (and more!) is simply and concisely documented on the Processing reference Web pages (http:%%//%%processing.org/reference/) under the **Color** and **Attributes** headings.
 === Canvas size ===
@@ Line 382: / Line 489: @@
 </code>
 Aaah ... that's better. Now we have some room to work.
+The call to the ''%%size%%'' function doesn't need to be the first statement in the ''%%setup%%'' function, but in this case it makes it easier for the reader if it is.

Programming Fundamentals with Processing

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