pdf to image c# open source: Extract data from pdf file to excel SDK Library service wpf .net html dnn fulton

function gameLoop() {

window.setTimeout(gameLoop, 20);

drawScreen()

}

gameLoop();

}

</script>

</head>

<body>

Your browser does not support the HTML 5 Canvas.

</canvas>

</div>

</body>

</html>

In Example 2-28, we first create a variable called yOffset and set it to be 0. Next, we

add a Canvas clearing function to our drawScreen() function. We then draw our path,

adding the yOffset to each y-axis value.

As shown in Chapter 1, we create a gameLoop() function that we call a single time, and

it, in turn, uses a setTimeout() function call to recursively call itself every 20 millisec‐

onds. This results in the drawScreen() function repeatedly being called. At the bottom

of the drawScreen() function, we simply add 1 to the current value of yOffSet. This

will create the illusion of the drawn path moving down the screen.

Checking to See Whether a Point Is in the Current Path

You can easily test whether a certain point is in the current path by using the isPoin

tInPath() Canvas function:

context.strokeStyle = "red";

context.lineWidth=5;

context.moveTo(0, 0);

context.lineTo(50, 0);

context.lineTo(50,50);

context.stroke();

var isPoint1InPath1=context.isPointInPath(0, 0);

var isPoint1InPath2=context.isPointInPath(10, 10);

console.log("isPoint1InPath1=" + isPoint1InPath1);

console.log("isPoint1InPath2=" + isPoint1InPath2);

context.closePath();

Checking to See Whether a Point Is in the Current Path | 79

Extract data from pdf file to excel - extract form data from PDF in C#.net, ASP.NET, MVC, Ajax, WPF

Help to Read and Extract Field Data from PDF with a Convenient C# Solution

extract data from pdf to excel online; can reader edit pdf forms

Extract data from pdf file to excel - VB.NET PDF Form Data Read library: extract form data from PDF in vb.net, ASP.NET, MVC, Ajax, WPF

Convenient VB.NET Solution to Read and Extract Field Data from PDF

export pdf form data to excel; pdf form field recognition

The first point, (0,0), is in the current path and will output true to the console, while

the second point, (10,10), is not and will output false to the console.

This doesn’t work the same in all browsers, yet. Compatibility is con‐

tinuing to improve with each new browser build. You will need to test

across a selection of browsers to see which have added full compatibility

with this function.

Drawing a Focus Ring

Digging further into the Canvas Specification, we find some functions that have not yet

been implemented. The drawCustomFocusRing() function applies to the Canvas cur‐

rent path and is used for accessibility. The context.drawSystemFocusRing(element)

function should allow the given element to have a focus ring drawn around the current

default path. Currently, almost no browsers support this function. Eventually, you

should be able to apply this to the Canvas and also check to see whether the focus ring

should be displayed by using the following function: var shouldDraw = context.draw

CustomFocusRing(theCanvas);. If this returns true, a custom focus ring on the current

path should be displayed.

What’s Next?

We covered a lot of ground in this chapter, introducing the ways to construct primitive

and complex shapes, and how we can draw and transform them on the canvas. We also

discussed how to composite, rotate, scale, translate, fill, and create shadows on these

shapes. But we’ve only just begun exploring HTML5 Canvas. In the next chapter, we

will look at how to create and manipulate text objects on the canvas.

80 | Chapter 2: Drawing on the Canvas

C# PDF Text Extract Library: extract text content from PDF file in

Able to extract and get all and partial text content from PDF file. How to C#: Extract Text Content from PDF File. Add necessary references:

exporting data from excel to pdf form; save data in pdf form reader

VB.NET PDF Text Extract Library: extract text content from PDF

Extract and get partial and all text content from PDF file. Extract highlighted text out of PDF document. Extract Text Content from PDF File in VB.NET.

export pdf data to excel; extracting data from pdf to excel

CHAPTER 3

The HTML5 Canvas Text API

The HTML5 Canvas Text API allows developers to render text on an HTML page in

ways that were either tricky or next to impossible before its invention.

We are providing an in-depth analysis of the HTML5 Canvas Text API because it is one

of the most basic ways to interact with the canvas. However, that does not mean it was

the first Canvas API feature developed. In fact, for many browsers, it was one of the last

parts implemented.

There was a time in the recent past when HTML5 Canvas Text API support in browsers

was spotty at best. Back then, using modernizr.js to test for text support would have been

a good idea. However, at this historic moment, all modern browser versions support

the HTML5 Canvas Text API in some way.

This chapter will create an application named “Text Arranger” to demonstrate the fea‐

tures and interdependencies of the HTML5 Canvas Text API. This application will dis‐

play a single line of text in an almost infinite number of ways. This is also a useful tool

to see whether support for text is common among web browsers. Later in this chapter,

you will see that some text features are incompatible when drawn on the canvas at the

same time.

Canvas Text and CSS

The first thing you need to know about text on HTML5 Canvas is that it does not use

CSS for style. While the properties of HTML5 Canvas look similar to CSS properties,

they are not interchangeable. While your knowledge of CSS will help you understand

text on the HTML5 Canvas, you can’t rely solely on that knowledge to be successful with

Canvas text. That being said, Canvas can take advantage of fonts defined in a CSS file

using @font-face, and can fall back to multiple different fonts if the defined font is not

available.

VB.NET Create PDF from Excel Library to convert xlsx, xls to PDF

Image: Insert Image to PDF. Image: Remove Image from PDF Page. Image: Copy, Paste, Cut Image in Page. Data: Read, Extract Field Data. Data: Auto Fill-in Field

extract data from pdf file; extract data from pdf file to excel

VB.NET PDF File Compress Library: Compress reduce PDF size in vb.

External cross references. Private data of other applications. Flatten visible layers. VB.NET Demo Code to Optimize An Exist PDF File in Visual C#.NET Project.

extracting data from pdf files; extract data out of pdf file

Displaying Basic Text

Displaying text on HTML5 Canvas is simple. We covered the basics in Chapter 1. Here,

we will review these basics, and then we will show you how to make them work with

the Text Arranger application.

Basic Text Display

The simplest way to define text to be displayed on the canvas is to set the con

text.font style by using standard values for CSS font style attributes: font-style,

font-weight, font-size, and font-face.

We will discuss each of these attributes in detail in the upcoming section “Setting the

Text Font” on page 89. All you need to know now is that a font designation of some type

is required. Here is a simple example of setting a 50-point serif font:

context.font = "50px serif";

You also need to set the color of the text. For filled text, you would use the context.fill

Style attribute and set it using a standard CSS color, or with a CanvasGradient or

CanvasPattern object. We will discuss the latter two options later in the chapter.

Finally, you call the context.fillText() method, passing the text to be displayed and

the x and y positions of the text on the canvas.

The following is an example of all three basic lines of code required to display filled text

on HTML5 Canvas:

context.font = "50px serif"

context.fillStyle = "#FF0000";

context.fillText ("Hello World", 100, 80);

If you do not specify a font, the default 10px sans-serif will be used automatically.

Handling Basic Text in Text Arranger

For Text Arranger, we are going to allow the user to set the text displayed by the call to

context.fillText(). To do this, we will create a variable named message where we

will store the user-supplied text. We will later use that variable in our call to con

text.fillText(), inside the standard drawScreen() method that we introduced in

Chapter 1 and will continue to use throughout this book:

var message = "your text";

...

function drawScreen() {

...

context.fillStyle = "#FF0000";

82 | Chapter 3: The HTML5 Canvas Text API

VB.NET PDF File Merge Library: Merge, append PDF files in vb.net

Microsoft Office Word, Excel and PowerPoint data to PDF form. Merge PDF with byte array, fields. Merge PDF without size limitation. Append one PDF file to the end

extract data from pdf form to excel; how to make a pdf form fillable in reader

C# PDF File Merge Library: Merge, append PDF files in C#.net, ASP.

Merge Microsoft Office Word, Excel and PowerPoint data to PDF form. Append one PDF file to the end of another and save to a single PDF file.

how to save filled out pdf form in reader; exporting pdf data to excel

context.fillText (message, 100, 80);

}

To change the text displayed on the canvas to the text entered by the user, we need to

create an event handler for the text box keyup event. This means that whenever someone

changes text in the box, the event handler function will be called.

To make this work, we are going to name our text box in our HTML <form> using an

<input> form element. Notice that the id is set to the value textBox. Also notice that

we have set the placeholder="" attribute. This attribute is new to HTML5, so it might

not work in every browser. You can also substitute it with the value="" attribute, which

will not affect the execution of this application:

<form>

Text: <input id="textBox" placeholder="your text"/>

<br>

</form>

Communicating Between HTML Forms and the Canvas

Back in our JavaScript code, we need to create an event handler for the keyup event of

textBox. We do this by finding the form element by using the document.getElement

ById() function of the DOM document object and storing it in the formElement variable.

Then we call the addEventListener() method of formElement, setting the event to

keyup and the event handler to the function textBoxChanged, which we have yet to

define:

var formElement = document.getElementById("textBox");

formElement.addEventListener('keyup', textBoxChanged, false);

The final piece of the puzzle is to define the textBoxChanged() event handler. This

function works like the event handlers we created in Chapter 1. It is passed one param‐

eter when it is called, an event object that we universally name e because it’s easy to

remember.

The event object contains a property named target that holds a reference to the HTML

form element that created the change event. In turn, the target contains a property

named value that holds the newly changed value of the form element that caused the

event to occur (that is, textBox). We retrieve this value and store it in the message

variable we created in JavaScript. It is the very same message variable we use inside the

drawScreen() method to paint the canvas. Now, all we have to do is call

drawScreen(), and the new value of message will appear “automagically” on the canvas:

function textBoxChanged(e) {

var target = e.target;

message = target.value;

drawScreen();

}

Displaying Basic Text | 83

C# Create PDF from Excel Library to convert xlsx, xls to PDF in C#

Library. Best Microsoft Office Excel to adobe PDF file converter SDK for Visual Studio .NET. Merge all Excel sheets to one PDF file. Export

extract table data from pdf to excel; pdf form save with reader

C# PDF File Compress Library: Compress reduce PDF size in C#.net

All object data. File attachment. External cross references. Private data of other applications. Flatten visible layers. C#.NET DLLs: Compress PDF Document.

cannot save pdf form in reader; extract data from pdf using java

We just spent a lot of time describing how we will handle changes in HTML form

controls with event handlers in JavaScript and then display the results on an HTML5

Canvas. We will repeat this type of code several more times while creating Text Arranger.

However, we will refrain from explaining it in depth again, instead focusing on different

ways to render and capture form data and use it with Canvas.

Using measureText

The HTML5 Canvas context object includes a useful method, measureText(). When

supplied with a text string, it will return some properties about that text, based on the

current context settings (font face, size, and so on) in the form of a TextMetrics object.

Right now, the TextMetrics object has only a single property: width. The width prop‐

erty of a TextMetrics object gives you the exact width in pixels of the text when rendered

on the canvas. This can be very useful when attempting to center text.

Centering text using width

For the Text Arranger application, we will use the TextMetrics object to center the text

the user has entered in the textBox form control on the canvas. First, we retrieve an

instance of TextMetrics by passing the message variable (which holds the text we are

going to display) to the measureText() method of the 2D context and storing it in a

variable named metrics:

var metrics = context.measureText(message);

Then, from the width property of metrics, we get the width value of the text in pixels

and store it in a variable named textWidth:

var textWidth = metrics.width;

Next, we calculate the center of the screen by taking the width value of the canvas and

dividing it in half (theCanvas.width/2). From that, we subtract half the width value of

the text (textWidth/2). We do this because text on the canvas is vertically aligned to the

left when it is displayed without any alignment designation (more on this a bit later).

So, to center the text, we need to move it half its own width to the left and place the

center of the text in the absolute center of the canvas. We will update this in the next

section when we allow the user to select the text’s vertical alignment:

var xPosition = (theCanvas.width/2) - (textWidth/2);

What about the height of the text?

So, what about finding the height of the text so that you can break text that is longer

than the width of the canvas into multiple lines, or center it on the screen? Well, this

poses a problem. The TextMetrics object does not contain a height property. The text

font size does not give the full picture either, because it does not take into account font

glyphs that drop below the baseline of the font. While the font size will help you estimate

84 | Chapter 3: The HTML5 Canvas Text API

how to center a font vertically on the screen, it does not offer much if you need to break

text into two or more lines. This is because the spacing would also need to be taken into

account, which could be very tricky.

For our demonstration, instead of trying to use the font size to vertically center the text

on the canvas, we will create the yPosition variable for the text by simply placing it at

one-half the height of the canvas. The default baseline for a font is middle, so this

works great for centering on the screen. We will talk more about baseline in the next

section:

var yPosition = (theCanvas.height/2);

In the chat example in Chapter 11, we will show you an example of

breaking up text onto multiple lines.

fillText and strokeText

The context.fillText() function (as shown in Figure 3-1) will render solid-colored

text to the canvas. The color used is set in the context.fillColor property. The font

used is set in the context.font property. The function call looks like this:

fillText([text],[x],[y],[maxWidth]);

where:

text

The text to render on the canvas.

The x position of the text on the canvas.

The y position of the text on the canvas.

maxWidth

The maximum width of the text as rendered on the canvas. At the time of this

writing, support for this property was just being added to browsers.

Displaying Basic Text | 85

Figure 3-1. fillText in action

The context.strokeText() function (as shown in Figure 3-2) is similar, but it specifies

the outline of text strokes to the canvas. The color used to render the stroke is set in the

context.strokeColor property; the font used is set in the context.font property. The

function call looks like:

strokeText([text],[x],[y],[maxWidth])

where:

text

The text to render on the canvas.

The x position of the text on the canvas.

The y position of the text on the canvas.

maxWidth

The maximum width of the text as rendered on the canvas. At the time of this

writing, this property does not appear to be implemented in any browsers.

86 | Chapter 3: The HTML5 Canvas Text API

Figure 3-2. strokeText setting outline properties

The next iteration of Text Arranger adds the ability for the user to select fillText,

strokeText, or both. Selecting both will give the fillText text a black border (the

strokeText). In the HTML <form>, we will add a <select> box with the id fillOr

Stroke, which will allow the user to make the selections:

<option value = "stroke">stroke</option>

</select>

In the canvasApp() function, we will define a variable named fillOrStroke that we

will use to hold the value selected by the user on the HTML <form>. The default value

will be fill, which means Text Arranger will always show fillText first:

var fillOrStroke = "fill";

We will also create the event listener for a change in the fillOrStroke form element:

formElement = document.getElementById("fillOrStroke");

formElement.addEventListener('change', fillOrStrokeChanged, false);

And create the function fillOrStrokeChanged() to handle the event:

function fillOrStrokeChanged(e) {

var target = e.target;

fillOrStroke = target.value;

drawScreen();

}

Displaying Basic Text | 87

eval()

While we created a separate function for each event handler for the applications in this

chapter, in reality, many of them work in an identical way. However, some developers

might be inclined to use an eval() function, such as the following, as their event handler

for changes made to the HTML element that controls Text Arranger:

var

formElement

document.getElementById("textBox");

formElement.addEventListener('keyup',

function(e)

{

applyChange('message',

false);

formElement

document.getElementById("fillOrStroke");

formElement.addEventListener('change',

function(e)

{

applyChange('fillOrStroke',

false);

function

applyChange

(variable,

{

eval(variable

' = e.target.value');

drawScreen();

}

The preceding code uses eval() to create and execute JavaScript code on the fly. It

dynamically creates the name of the HTML element so that the multiple event handler

functions do not need to be created individually. However, many developers are wary

of using eval() because it opens up security holes, and makes debugging code more

difficult. Use at your own risk.

In the drawScreen() function, we test the fillOrStroke variable to see whether it con‐

tains the value fill. Because we have three states (fill, stroke, or both), we use a

switch statement to handle the choices. If the choice is both, we set the strokeStyle

to black (#000000) as the highlight for the colored fillText.

If we use the xPosition and yPosition calculated using the width and height of the

canvas, the message variable that contains the default or user-input text, and the fil

lOrStroke variable to determine how to render the text, we can display the text as

configured by the user in drawScreen():

var metrics = context.measureText(message);

var textWidth = metrics.width;

var xPosition = (theCanvas.width/2) - (textWidth/2);

var yPosition = (theCanvas.height/2);

switch(fillOrStroke) {

case "fill":

context.fillStyle = "#FF0000";

context.fillText (message, xPosition,yPosition);

break;

case "stroke":

context.strokeStyle = "#FF0000";

context.strokeText (message, xPosition,yPosition);

88 | Chapter 3: The HTML5 Canvas Text API

Documents you may be interested

pdf to image c# open source : Extract data from pdf file to excel SDK Library service wpf .net html dnn fulton_fulton10-part519