B_OP_ADD drawing mode not working in SoundRecorder

[korli]

I noticed that B_OP_ADD isn't implemented when using SoundRecorder.

But it seems B_OP_ERASE, B_OP_INVERT, B_OP_SELECT, B_OP_MIN, B_OP_MAX, B_OP_SUBSTRACT, B_OP_BLEND aren't implemented too.

[stippi]

Could you please point to the code in SoundRecorder that does not work? As you can see in Playground, all drawing modes work fine there.

[korli]

OK, I didn't have a look at Playground to test. So forget my remark about other modes than B_OP_ADD.

In SoundRecorder, there is a B_OP_ADD set and StrokeLine done in ScopeView::RenderBitmap(). I can see something drawn when I replace with B_OP_OVER. ​http://svn.berlios.de/viewcvs/haiku/haiku/trunk/src/apps/soundrecorder/ ScopeView.cpp?rev=17718&view=markup

[korli]

Stephan, I could be wrong but I think the way the add is done will result in an overflow of the uint8 data type

uint8 rt = min_c(255, _p.data8[2] + (r));

=> if _p.data8[2] and r are uint8, and values are 130, 130, the value of rt will be : 5 instead of 255. Thus it should IMO be (optimizations could be done): uint8 rt = min_c(255, (uint16)_p.data8[2] + (uint16)(r));

[korli]

In fact, I was wrong, forget my last comment.

[korli]

I committed a fix in revision 18050. Not very good IMO. Stephan, it would be cool if you could review this. Thanks.

[korli]

Fixed by stippi. Thanks. Though there is a big performance hit compared with Dano (at least x5). Maybe we should make an optimized StrokeLine for 1 pixel. Also, is it valid to draw a square (0,0,1,1) to actually draw a single point ?