iB::Topic::EasyBoot 4bit colors

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Topic: EasyBoot 4bit colors, incorrect rendering

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Post Number: 1

mionica

Group: Members
Posts: 49
Joined: Apr. 2005

Posted on: Mar. 23 2006,18:05

Sir (xoben),

please review the following thread first: this post.

As you well know, the 640x480x4 video mode supports colors by using a certain 16-items palette; therefore, the background image is displayed using the color table stored inside the .ezb file.

However, I find this to be utterly inappropriate behavior, as it leads to (apparent) screen corruption when the CD is booted.

I should mention that the rendering in the preview window of EasyBoot is incorrect, in this respect (this is why I chose to post in the "bugs" forum instead of the "suggestions" one).

I suggest this matter be adressed as follows:
1. Change the preview code to use the .ezb color table when rendering the background bitmap (in the 640x480x4 mode);
2. Offer an option to import into the .EZB the color table from the .BMP file when choosing it, if the selected mode is the legacy one (for the VESA ones, it would be quite useless).

There would be a second problem, too. Your mouse drawing code is hardcoded to use the first and the last entries in the palette. This may lead to unfortunate looks of the boot CD interface, if color 0x00 is not the darkest and/or color 0x0f is not the lightest.

Since there is no way to guarantee the palette is sorted by brightness by default, I see two reasonable approaches to this issue:
1. You may choose to silently order the palette in the .BMP file upon opening

Code Sample

luminance( R, G, B )=sqrt( sqr( R ) + sqr( G ) + sqr ( B ) )

2. Even better - let the user choose the colors to be used for drawing the mouse.

Looking forward to hear from you,
Mircea.