Win32 - speaking on RECT: what is the diference between the PAINTSTRUCT hdc and memory HDC?

Question

see these code:
RECT b={test.rcPaint.left+2, test.rcPaint.top, test.rcPaint.right-2, test.rcPaint.bottom};
imglabel.DrawText(inst->strCaption, b);
//DrawText() from my image class:
void DrawText(string strText,RECT HDCrect)
char *text=(char*)strText.c_str();
DrawTextEx(HBitmap,text,-1,&HDCrect,DT_LEFT,NULL);
what is the deference, speaking on RECT, between PAINTSTRUCT hdc and memory HDC?
if i do top=1 or left=1, the Region reault is changed too :(

Answer 1

i was getting  problems between the image size and bottom\right, with Regions.
see these function on my image class:
void DrawText(string strText,int PosX=0, int PosY=0)
// geting the text rectangle
RECT r = { 0, 0, 0, 0 };
char *text=(char*)strText.c_str();
::DrawText(HBitmap, text, -1, &r, DT_CALCRECT);
//change the position of the text
r.left=PosX;
r.top=PosY;
r.bottom=r.bottom+PosY;
r.right=r.right+PosX;
//draw the text
::DrawText(HBitmap, text, -1,&r,DT_LEFT);
and see how i use it:
imglabel.DrawText(inst->strCaption);//inst my label object pointer
//imglabel is my image object
if(inst->blnTransparent==true)
//draw the image
TransparentBlt(test.hdc,0,0,imglabel.width(),imglabel.height(),imglabel,0,0, imglabel.width(),imglabel.height(), inst->clrBackColor);
//destroy the region
SetWindowRgn(inst->hwnd,NULL,TRUE);
//Create and set them region
inst->LabelRegion=RegionbyBitmap(imglabel, inst->clrBackColor);
SetWindowRgn(inst->hwnd,inst->LabelRegion,TRUE);
if i don't destroy the Region, before use the new Region, i get a size problem(less pixels).
by some reason the text RECT can affect the Region size :(