The black magic of GDI+

One of the things I am most ashamed of on Quivi is its speed when opening large images (which are not uncommon nowadays, specially with digital photos). It’s embarrassing that the lame Windows Picture and Fax Viewer is lightning fast when opening those images!

I’ve always wondered how the Viewer did that. I’ve searched about it in the past but could never find anything about it. Then one of these days I was browsing the Wikipedia page about the Viewer and there I learned that it uses GDI+.

GDI+ is a C++ library, but it is built upon a flat C API which I could easily use in Python via ctypes. Long story short, I was able to modify Quivi to add support for viewing images with GDI+. And the result was amazing!

What about Linux? Well, something “equivalent” to GDI+ would be Cairo, so I did some tests with it too (luckily, support for it was included in wxPython recently).

Here are the results for the time to load a huge 5704px x 5659px PNG image and rescale it to 1/20 of its size:

Time to load and scale a PNG image
Library Time (s)
FreeImage 10.38
PIL 9.90
GDI+ 2.22
Cairo (from FreeImage) 3.60
Cairo (direct) 3.28

The reason for the two Cairo timings is that it supports reading directly from a PNG file but for e.g. JPG files you need to read the image with another library and to the format Cairo uses. I’ve used FreeImage to load the image and converted it to a Cairo surface.

Here are the results for the time to load and scaling the same image, but as a JPG:

Time to load and scale a JPG image
Library Time (s)
FreeImage 6.91
PIL 8.38
GDI+ 0.19
Cairo (from FreeImage) 1.43

Scary! How does GDI+ manages to do that? According to Wikipedia it uses hardware acceleration… Cairo doesn’t lag begind considering that the scaling only takes 0.015 (!) but I did notice that even its best quality scaling isn’t so good in comparison to the others, which is kinda odd.

Anyway, I’ll try to release a new version of Quivi with GDI+ and Cairo support soon. Stay tuned.

Quivi for Linux released

I’ve just released the Linux version of Quivi:

Quivi is an image viewer (specialized for comic/manga reading) for Windows which supports many file formats and compressed (zip, rar) files. It is aimed for fast & easy file browsing with keyboard or mouse.

It was working on Linux for a while, but now it’s “official”. I’ve released a .deb package which was tested on Ubuntu and may work on Debian. There’s also, of course, the source code, which requires some dependencies to be installed. You can grab both at the download page.

Help on packaging is much welcome, since I don’t have any experience releasing stuff for Linux. And please tell me if there is anything wrong with the release.

Quivi 1.0 released

I’ve just released the new version of my image viewer and manga / comic reader, Quivi (only for Windows right now, but it will be ported to Linux and maybe to Mac). I’ve rewritten it from scratch, check my last post for more info.

The new features added were:

  • Prefetching of the next image
  • Wallpaper dialog
  • Start directory option

But that is only the beginning; now it will be much more easy for me to work on Quivi.

There are many comic readers around; like CDisplay (outdated, but very popular), Comical and Comix. They have much more features than Quivi, and I must admit that I often thought on giving up on Quivi. But I just couldn’t.

I wrote it mainly for myself; when I started there was only CDisplay. The first version was written with Visual Basic (go on, laugh). Then I changed to C++. And now I changed to Python, and I hope this is the last language change 🙂 It’s a hobby project that I grew to love. It suits my needs, but I’d really like to suit the needs of other people too!

It is scary when you realize that people are using your software. I feel responsible; wherever I find someone criticizing it, I feel guilty for not attending those people needs. Yes, that’s stupid, but it’s how I am. At the same time, though, it’s awesome to know that there are people who like it and find it useful.

If you have any suggestion, comment, complain about Quivi, please send it to me!

Why I rewrote Quivi from scratch

Joel Spolsky, popular software engineering, said in this blog:

(…) They [Netscape] did it by making the single worst strategic mistake that any software company can make:

They decided to rewrite the code from scratch.

I agree, mostly. Many projects market that they’ve been “rewritten from scratch” as if it was something marvelous, and most of time, it’s just a sign that the new version probably has more bugs than the previous. But, wait, I just rewrote Quivi (a image viewer and comic / manga reader) from scratch! Well, why?

Well, I thought I really had to justify this. So here are the reasons:

  • It is a small project. Rewriting it certainly isn’t as hard as rewriting a browser!
  • I couldn’t stand C++ anymore (the programming language I used before). Of course, this isn’t C++ fault per se. It has its uses — the right tool for the right job, and so on. But to write an desktop application? It’s overkill. If you manage to pull it of, hey, kudos to you. But I had no motivation to work on it anymore.
  • I love Python (the programming language I use now), and of course, I’m not the only one. Programming is fun in Python, so much that had the motivation to rewrite Quivi from scratch in the first place! And of course, it will be much more easier for me to keep working on Quivi.
  • I could change GUI libraries. SmartWin is a nice library, and uses templates in very interesting ways; when programming Quivi I ended up involved with its development too. But it has its bugs, and because it uses templates extensively, it’s awful slow to compile an application that uses it. I’ve changed to wxPython, which is a very mature GUI library – and cross platform to boot.

Of course, there are some downsides with the change. The whole software package is much bigger due to the dependencies (the installer jumped from 900K to 5MB!). And the program is a little bit slower, mainly when starting up, and uses more memory (9MB to 30MB with no images loaded). But I think it was a good enough trade-off.

Rewriting from scratch must be considered carefully, and in this case, I think it was a good idea. Quivi is a hobby project, and I guess the main point of it is to have fun writing it, and to make users happy. I hope I can do both with this new version (which will be released soon).