I'm making a slider widget with a <canvas>.
First I draw the background. I'd like to save this drawing. Something
like:
slider.drawBack ground();
slider.back = new ScreenArea( left, top, width, height );
Next, draw the pointer. When the user slides the slider, I'd like to
restore the saved background and then redraw the pointer. Any way of
doing this directly? Something like:
slider.back.res tore();
slider.drawPoin ter();
I've been playing with indirection: using context.toDataU RL() (after
drawing the background) but I haven't found a way to take that string
and use it to construct an Image object. What I want is:
slider.back = new Image( context.toDataU RL() ); // in my dreams!
Or maybe:
slider.back = new Image( wid, hgt );
slider.back.src = context.toDataU RL(); // still dreaming 8 2890
On Oct 22, 1:12*pm, MartinRineh...@ gmail.com wrote:
I'm making a slider widget with a <canvas>.
Why?
On Oct 22, 7:12 pm, MartinRineh...@ gmail.com wrote:
(...)
I've been playing with indirection: using context.toDataU RL() (after
drawing the background) but I haven't found a way to take that string
and use it to construct an Image object. What I want is:
slider.back = new Image( context.toDataU RL() ); // in my dreams!
Or maybe:
slider.back = new Image( wid, hgt );
slider.back.src = context.toDataU RL(); // still dreaming
var img= document.create Element('img');
img.src= context.toDataU RL();
--
Jorge.
David Mark wrote:
On Oct 22, 1:12�pm, MartinRineh...@ gmail.com wrote:
I'm making a slider widget with a <canvas>.
Why?
Because I need a slider for my color chooser which I'm writing after
asking my very smart friend Mr. Google about JS color choosers. He led
me to many. But when I said "I want to be able to pick a color by
clicking in a color wash, by supplying RGB values, by entering hex or
by picking from a palette of recent choices, Mr. Google told me I was
on my own.
Jorge wrote:
var img= document.create Element('img');
img.src= context.toDataU RL();
Thank you!
Any reason why this works but 'new Image()' doesn't?
On Oct 23, 3:29*pm, MartinRineh...@ gmail.com wrote:
Jorge wrote:
var img= document.create Element('img');
img.src= context.toDataU RL();
Thank you!
Any reason why this works but 'new Image()' doesn't?
No idea. I didn't know that new Image() existed. What other tags have
a constructor ?
--
Jorge.
Still not working. Here I've got a second 'test' canvas. Attempt to
save image and redraw in the test area. Code:
var img = document.create Element( 'img' );
img.src = slider.canvas.t oDataURL( 'image/png' );
alert( img.src.length )
var t = document.getEle mentById( 'test' );
var pen2 = t.getContext( '2d' );
pen2.drawImage( img, 0, 0 );
This is called after painting the background from <bodyonload() . The
alert() gives different results (from a low around 250 to a high over
10,000).
P.S. WORKING! I have no clue why. Trivial change, looks functionally
identical.
var img = document.create Element( 'img' );
var str = slider.canvas.t oDataURL( 'image/png' );
alert( str.length )
img.src = str;
var t = document.getEle mentById( 'test' );
var pen2 = t.getContext( '2d' );
pen2.drawImage( img, 0, 0 );
The alert gives different results, but in the 300 to 315 range.
Jorge wrote:
No idea. I didn't know that new Image() existed. What other tags have
a constructor ?
Since 'document.creat eElement()' works and 'new Image()' doesn't, I'm
going to pretend the former is the real constructor.
On Oct 23, 8:05*pm, MartinRineh...@ gmail.com wrote:
Jorge wrote:
No idea. I didn't know that new Image() existed. What other tags have
a constructor ?
Since 'document.creat eElement()' works and 'new Image()' doesn't, I'm
going to pretend the former is the real constructor.
document.create Element('img') way of creating an image object is a
part of the DOM specification; new Image() isn't. The valid
invocations of the Image constructor are:
var i = new Image();
i.src = 'images/ah.png';
var i = new Image(250 /*width*/, 250 /*height*/);
i.src = 'images/ah.png';
/sasuke This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Andras Gilicz |
last post by:
Hi VB fans
I'm working on a relatively large project in VB6 with about a dozen
forms, including graphs, labels, text boxes, etc. The software itself
is actually a flow simulator with more or less complex technical
calculations, several input variables. I would like to equipp the
starting panel with the usual New, Open, Save, Save As, Close etc.
menus (like in Excel, or Word, etc.) What is the best way to
accomplish Save, or Save As?...
|
by: Dave Romig |
last post by:
Can anyone provide guidance for saving and restoring an XMLDOM object as a
binary blob? In a VB application, I need to repeatedly save and restore a
large, dynamic XML document. Currently, the CPU overhead of serialization
and de-serialization is KILLING performance.
I have done some tests and if I could persist the DOM as a binary blob, I
think the performance issues would be resolved. A pair of orthogonal
functions that translate...
|
by: Paul Sullivan |
last post by:
We are a state agency that views protected medical information via our
intranet. The screens even have privacy shields. Alarmingly, uses can
"Print" and "Save As" which destroys the protection of the health
information at the level we want.
QUESTION: Can we shut those off?? Any other suggestions??
Paul Sullivan
|
by: JezB |
last post by:
There are a few references on the net about how to restore a page's scroll
position over a postback. This is a simple one which works for me:
eg. http://www.devhood.com/messages/message_view-2.aspx?thread_id=104625
My question is : can the same thing be done to restore the scroll position
of a specific DIV within a page? I have a DIV section which scrolls
independently to the page :
<div style="vertical-align: top; height:200px;...
|
by: Wayne |
last post by:
I have found the following code on this newsgroup that removes the
Access Application minimize, restore and close buttons.
Private Const GWL_EXSTYLE = (-20)
Private Const GWL_STYLE = (-16)
Private Const WS_MAXIMIZEBOX = &H10000
Private Const WS_MINIMIZEBOX = &H20000
Private Const WS_SYSMENU = &H80000
| |
by: fdu.xiaojf |
last post by:
Hi,
I have a program which will continue to run for several days. When it is
running, I can't do anything except waiting because it takes over most
of the CUP time.
Is it possible that the program can save all running data to a file when
I want it to stop, and can reload the data and continue to run from
where it stops when the computer is free ?
|
by: Joe |
last post by:
does anyone know why this source code throws an error??
Dim myBitmap As System.Drawing.Bitmap
Dim myGraphics As Graphics
myBitmap = New System.Drawing.Bitmap(fileName:="C:\test.tif")
myGraphics = PictureBox1.CreateGraphics
Dim expansionRectangle As New Rectangle(25, 550, 1000, 350)
Dim destRectangle1 As New Rectangle(0, 0, 1000, 350)
myGraphics.DrawImage(myBitmap, destRectangle1, expansionRectangle,
|
by: Alan Forsyth |
last post by:
That rather long subject says it.
In Access97 running on XP - I want to display a Maximized size Form01, then
open a Restore size Datasheet View Form02 on top of the first Form.
PopUp won't give me Datasheet view.
Dialog mode won't give me Datasheet view
I could make Form01 Restore size and expand it to fill the Window in
Restore size (maybe DoCmd.MoveSize Right, Down, Width, Height) - I don't
want this.
|
by: mike |
last post by:
I have the opportunity to rescue a project that
uses a mouse to sense the relative position of a machine.
The hardware is built...just needs to be programmed.
Stop snickering!!! I didn't do it...I just gotta fix it.
I need to make some calculations on the measurements
and VB6 is my language.
Yes, the system mouse will corrupt the measurement,
but it's an auditing function and that's acceptable.
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
| |
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
| |
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
| |