convert pdf to image c# free: Extract pdf data into excel SDK application API .net html winforms sharepoint fulton

xor

Source xor destination. Exclusive OR of the source image and destination image.

Example 2-6 shows how some of these values can affect how shapes are drawn to the

canvas, producing Figure 2-11.

Example 2-6. Canvas compositing example

function drawScreen() {

//draw a big box on the screen

context.fillStyle = "black"; //

context.fillRect(10, 10, 200, 200);

//leave globalCompositeOperation as is

//now draw a red square

context.fillStyle = "red";

context.fillRect(1, 1, 50, 50);

//now set it to source-over

context.globalCompositeOperation = "source-over";

//draw a red square next to the other one

context.fillRect(60, 1, 50, 50); //now set to destination-atop

context.globalCompositeOperation = "destination-atop";

context.fillRect(1, 60, 50, 50);

//now set globalAlpha

context.globalAlpha = .5;

//now set to source-atop

context.globalCompositeOperation = "source-atop";

context.fillRect(60, 60, 50, 50);

}

Figure 2-11. Canvas compositing example

Compositing on the Canvas | 49

Extract pdf data into 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 form to excel; extracting data from pdf forms to excel

Extract pdf data into 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

fill in pdf form reader; pdf data extraction to excel

Unfortunately context.globalCompositeOperation = "destination-

atop" does not work properly in browsers any more.

As you can see in this example, we have toyed a little with both the globalComposi

teOperation and the globalAlpha Canvas properties. When we assign the string

source-over, we are essentially resetting the globalCompositeOperation back to the

default. We then create some red squares to demonstrate a few of the various compo‐

siting options and combinations. Notice that destination-atop switches the newly

drawn shapes under the current Canvas bitmap and that the globalAlpha property

affects only shapes that are drawn after it is set. This means that we don’t have to use

the save() and restore() functions for the Canvas state to set the next drawn shape

to a new transparency value.

In the next section, we will look at some transformations that affect the entire canvas.

As a result, if we want to transform only the newly drawn shape, we will have to use the

save() and restore() functions.

Simple Canvas Transformations

Transformations on the canvas refer to the mathematical adjustment of physical prop‐

erties of drawn shapes. The two most commonly used shape transformations are scale

and rotate, which we will focus on in this section.

Under the hood, a mathematical matrix operation applies to all transformations. Luckily,

you do not need to understand this to use simple Canvas transformations. We will

discuss how to apply rotation, translation, and scale transformations by changing simple

Canvas properties.

Rotation and Translation Transformations

An object on the canvas is said to be at the 0 angle rotation when it is facing to the left.

(This is important if an object has a facing side; otherwise, we will use this as a guide.)

Consequently, if we draw an equilateral box (all four sides are the same length), it doesn’t

have an initial facing side other than one of the flat sides facing to the left. Let’s draw

that box for reference:

//now draw a red square

context.fillStyle = "red";

context.fillRect(100,100,50,50);

Now, if we want to rotate the entire canvas 45 degrees, we need to do a couple simple

steps. First, we always set the current Canvas transformation to the “identity” (or “reset”)

matrix:

50 | Chapter 2: Drawing on the Canvas

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

Turn all Excel spreadsheet into high quality PDF without losing formatting. Evaluation library and components for PDF creation from Excel in C#.NET framework.

make pdf form editable in reader; cannot save pdf form in reader

C# PDF insert text Library: insert text into PDF content in C#.net

Parameters: Name, Description, Valid Value. value, The char wil be added into PDF page, 0

filling out pdf forms with reader; c# read pdf form fields

context.setTransform(1,0,0,1,0,0);

Because Canvas uses radians, not degrees, to specify its transformations, we need to

convert our 45-degree angle into radians:

var angleInRadians = 45 * Math.PI / 180;

context.rotate(angleInRadians);

Lesson 1: Transformations are applied to shapes and paths drawn after the setTransform() or

other transformation function is called

If you use this code verbatim, you will see a funny result...nothing! This is because the

setTransform() function call affects only shapes drawn to the canvas after it is applied.

We drew our square first and then set the transformation properties. This resulted in

no change (or transform) to the drawn square. Example 2-7 gives the code in the correct

order to produce the expected result, as illustrated in Figure 2-12.

Example 2-7. Simple rotation transformation

function drawScreen() {

//now draw a red square

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 45 * Math.PI / 180;

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(100,100,50,50);

}

Figure 2-12. Simple rotation transformation

We get a result this time, but it will probably differ from what you expect. The red box

is rotated, but it looks like the canvas was rotated with it. The entire canvas did not

rotate, only the portion drawn after the context.rotate() function was called. So, why

did our square both rotate and move off to the left of the screen? The origin of the

rotation was set at the “nontranslated” 0,0 position, resulting in the square rotating

from the top left of the entire canvas.

Example 2-8 offers a slightly different scenario: draw a black box first, then set the

rotation transform, and finally, draw the red box again. See the results in Figure 2-13.

Simple Canvas Transformations | 51

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

Field Data. Data: Auto Fill-in Field Data. Field: Insert & pages edit, C#.NET PDF pages extract, copy, paste NET Microsoft Office Excel to adobe PDF file converter

extract data from pdf to excel online; extracting data from pdf to excel

C# PDF Page Extract Library: copy, paste, cut PDF pages in C#.net

pdf"; doc.Save(outputFilePath); C#.NET Sample Code: Extract PDF Pages and Save into a New PDF File in C#.NET. You can easily get

extract data from pdf into excel; exporting pdf form to excel

Example 2-8. Rotation and the Canvas state

function drawScreen() {

//draw black square

context.fillStyle = "black";

context.fillRect(20,20,25,25);

//now draw a red square

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 45 * Math.PI / 180;

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(100,100,50,50);

}

Figure 2-13. Rotation and the Canvas state

The small black square was unaffected by the rotation, so you can see that only the

shapes drawn after the context.rotate() function was called were affected.

Again, the red box was moved far off to the left. To reiterate, this occurred because the

canvas did not know what origin to use for the rotation. In the absence of an actual

translated origin, the 0,0 position setting is applied, resulting in the context.ro

tate() function rotating “around” the 0,0 point, which brings us to our next lesson.

Lesson 2: We must “translate” the point of origin to the center of our shape to rotate it around

its own center

Let’s change Example 2-8 to rotate the red square 45 degrees while keeping it in its

current location.

First, we take the numbers we applied to the fillRect() function call to create a few

variables to hold the red square’s attributes. This is not necessary, but it will make the

code much easier to read and change later:

var x = 100;

var y = 100;

52 | Chapter 2: Drawing on the Canvas

C# PDF insert image Library: insert images into PDF in C#.net, ASP

Import graphic picture, digital photo, signature and logo into PDF document. Merge several images into PDF. Insert images into PDF form field.

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

VB.NET PDF Page Extract Library: copy, paste, cut PDF pages in vb.

Help to extract single or multiple pages from adobe PDF file and save into a new PDF file. VB.NET: Extract PDF Pages and Save into a New PDF File.

export pdf form data to excel spreadsheet; extract pdf form data to xml

var width = 50;

var height = 50;

Next, using the context.translate() function call, we must change the origin of the

canvas to be the center of the red square we want to rotate and draw. This function

moves the origin of the canvas to the accepted x and y locations. The center of our red

square will now be the desired top-left corner x location for our object (100), plus half

the width of our object. Using the variables we created to hold attributes of the red

square, this would look like:

x+0.5*width

Next, we must find the y location for the origin translation. This time, we use the y value

of the top-left corner of our shape and the height of the shape:

y+0.5*height

The translate() function call looks like this:

context.translate(x+0.5*width, y+0.5*height)

Now that we have translated the canvas to the correct point, we can do our rotation.

The code has not changed:

context.rotate(angleInRadians);

Finally, we need to draw our shape. We cannot simply reuse the same values from

Example 2-8 because the canvas origin point has moved to the center of the location

where we want to draw our object. You can now consider 125,125 as the starting point

for all draw operations. We get 125 for x by taking the upper-left corner of the square

(100) and adding half its width (25). We do the same for the y origin position. The

translate() method call accomplishes this.

We will need to draw the object starting with the correct upper-left coordinates for x

and y. We do this by subtracting half the width of our object from the origin x, and half

the height of our object from the origin y:

context.fillRect(-0.5*width,-0.5*height, width, height);

Why do we do this? Figure 2-14 illustrates the situation.

Consider that we want to draw our square starting at the top-left corner. If our origin

point is at 125,125, the top left is actually 100,100. However, we have translated our

origin so that the canvas now considers 125,125 to be 0,0. To start our box drawing at

the nontranslated canvas, we have to start at −25,−25 on the “translated” canvas.

This forces us to draw our box as though the origin is at 0,0, not 125,125. Therefore,

when we do the actual drawing of the box, we must use these coordinates, as shown in

Figure 2-15.

Simple Canvas Transformations | 53

C# PDF Page Insert Library: insert pages into PDF file in C#.net

from the ability to inserting a new PDF page into existing PDF PDF page or pages from various file formats, such as PDF, Tiff, Word, Excel, PowerPoint, Bmp

how to fill pdf form in reader; vb extract data from pdf

C# PDF File Split Library: Split, seperate PDF into multiple files

Divide PDF File into Two Using C#. This is an C# example of splitting a PDF to two new PDF files. Split PDF Document into Multiple PDF Files in C#.

save pdf forms in reader; how to fill out a pdf form with reader

Figure 2-14. The newly translated point

Figure 2-15. Drawing with a translated point

In summary, we needed to change the point of origin to the center of our square so that

it would rotate around that point. But when we draw the square, we need our code to

act as though the (125,125) point is actually (0,0). If we had not translated the origin,

we could have used the (125,125) point as the center of our square (as in Figure 2-14).

Example 2-9 demonstrates how this works, creating the result shown in Figure 2-16.

Example 2-9. Rotation around the center point

function drawScreen() {

//draw black square

context.fillStyle = "black";

context.fillRect(20,20 ,25,25);

//now draw a red square

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 45 * Math.PI / 180;

var x = 100;

var y = 100;

var width = 50;

var height = 50;

54 | Chapter 2: Drawing on the Canvas

context.translate(x+.5*width, y+.5*height);

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

}

Figure 2-16. Rotation around the center point

Let’s look at one final rotation example. Example 2-10 takes Example 2-9 and simply

adds four separate 40×40 squares to the canvas, rotating each one slightly. The result is

shown in Figure 2-17.

Example 2-10. Multiple rotated squares

function drawScreen() {

//now draw a red square

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 45 * Math.PI / 180;

var x = 50;

var y = 100;

var width = 40;

var height = 40;

context.translate(x+.5*width, y+.5*height);

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 75 * Math.PI / 180;

var x = 100;

var y = 100;

var width = 40;

var height = 40;

context.translate(x+.5*width, y+.5*height);

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

context.setTransform(1,0,0,1,0,0);

Simple Canvas Transformations | 55

var angleInRadians = 90 * Math.PI / 180;

var x = 150;

var y = 100;

var width = 40;

var height = 40;

context.translate(x+.5*width, y+.5*height);

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 120 * Math.PI / 180;

var x = 200;

var y = 100;

var width = 40;

var height = 40;

context.translate(x+.5*width, y+.5*height);

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

}

Figure 2-17. Multiple rotated squares

Next, we will examine scale transformations.

Scale Transformations

The context.scale() function takes in two parameters: the first is the scale attribute

for the x-axis, and the second is the scale attribute for the y-axis. The value 1 is the

normal scale for an object. Therefore, if we want to double an object’s size, we can set

both values to 2. Using the following code in drawScreen() produces the red square

shown in Figure 2-18:

context.setTransform(1,0,0,1,0,0);

context.scale(2,2);

context.fillStyle = "red";

context.fillRect(100,100 ,50,50);

56 | Chapter 2: Drawing on the Canvas

Figure 2-18. A simple scaled square

If you test this code, you will find that scale works in a similar manner as rotation. We

did not translate the origin of the scale point to double the size of the square; rather, we

used the top-left corner of the canvas as the origin point. The result is that the red square

appears to move farther down and to the left. What we would like is for the red square

to remain in place and to scale from its center. We do this by translating to the center

of the square before we scale, and by drawing the square around this center point (just

as we did in Example 2-9). Example 2-11 produces the result shown in Figure 2-19.

Example 2-11. Scale from the center point

function drawScreen() {

//now draw a red square

context.setTransform(1,0,0,1,0,0);

var x = 100;

var y = 100;

var width = 50;

var height = 50;

context.translate(x+.5*width, y+.5*height);

context.scale(2,2);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

}

Figure 2-19. Scale from the center point

Combining Scale and Rotation Transformations

If we want to both scale and rotate an object, Canvas transformations can easily be

combined to achieve the desired results (as shown in Figure 2-20). Let’s look in

Example 2-12 at how we might combine them by using scale(2,2) and rotate(an

gleInRadians) from our previous examples.

Simple Canvas Transformations | 57

Example 2-12. Scale and rotation combined

function drawScreen() {

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 45 * Math.PI / 180;

var x = 100;

var y = 100;

var width = 50;

var height = 50;

context.translate(x+.5*width, y+.5*height);

context.scale(2,2);

context.rotate(angleInRadians);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

}

Figure 2-20. Scale and rotation combined

Example 2-13 also combines rotation and scale, this time using a rectangle. Figure 2-21

reveals what it creates.

Example 2-13. Scale and rotate a nonsquare object

function drawScreen() {

//now draw a red rectangle

context.setTransform(1,0,0,1,0,0);

var angleInRadians = 90 * Math.PI / 180;

var x = 100;

var y = 100;

var width = 100;

var height = 50;

context.translate(x+.5*width, y+.5*height);

context.rotate(angleInRadians);

context.scale(2,2);

context.fillStyle = "red";

context.fillRect(-.5*width,-.5*height , width, height);

}

58 | Chapter 2: Drawing on the Canvas

Documents you may be interested

convert pdf to image c# free : Extract pdf data into excel SDK application API .net html winforms sharepoint fulton_fulton7-part584