Solved

Using TCanvas

Posted on 1998-05-30
1
320 Views
Last Modified: 2010-04-06
I have a bitmap that I load from a file and put into an integer array. To do this I draw the bitmap onto a canvas and then uses the canvas' pixels property to get the pixels into the array. The problem is it won't work if the canvas isn't a part of a VCL. When I made a variable of type TCanvas, and tried to draw the bitmap onto it I got a error message saying something like "Canvas does not allow drawing!". Everything worked fine when I drew onto the canvas of a TImage. What am I doing wrong? Is there a better way to do this without using the canvas?
0
Comment
Question by:red_2
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 3

Accepted Solution

by:
Matvey earned 100 total points
ID: 1349354
If you make an object variable you have to create it using TCanvas.Create, and assign it's parent. Are you sure that this is what you're doing?

Ahhh, wait... you can't create just canvas and draw on it - canvas represent something the user can see!! You have to use TBitmap for that or something like that...

You shouldn't use TCanvas like that - I'm sure.

Good luck!
Matvey
bosism@netvision.net.il
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

The uses clause is one of those things that just tends to grow and grow. Most of the time this is in the main form, as it's from this form that all others are called. If you have a big application (including many forms), the uses clause in the in…
Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
In an interesting question (https://www.experts-exchange.com/questions/29008360/) here at Experts Exchange, a member asked how to split a single image into multiple images. The primary usage for this is to place many photographs on a flatbed scanner…

734 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question