lel

farbfeld image viewer
git clone git://git.2f30.org/lel.git
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commit ab9cbe037f3c83444be66af5531f2f4bc61cb0c4
parent 77d29cab890dd1623b96d445cf0b898ff8c09df8
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Sat Aug  2 23:53:54 +0000

add alpha blending...

... and add configurable background colour.

Diffstat:
lel.c | 17++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/lel.c b/lel.c @@ -44,11 +44,14 @@ static struct img *cimg; static size_t nimgs; static int viewmode = ASPECT; static char *wintitle = APP_NAME; +static char *bgcolor = "#000000"; static XImage *ximg = NULL; static Drawable xpix = 0; static Display *dpy = NULL; +static Colormap cmap; static Window win; static GC gc; +static XColor bg; static int screen, xfd; static int running = 1; static int winwidth = 0, winheight = 0; @@ -231,6 +234,7 @@ scale(unsigned int width, unsigned int height, unsigned int bytesperline, { unsigned char *ibuf; unsigned int jdy, dx, bufx, x, y; + float a = 0.0f; jdy = bytesperline / 4 - width; dx = (cimg->width << 10) / width; @@ -239,9 +243,10 @@ scale(unsigned int width, unsigned int height, unsigned int bytesperline, ibuf = &cimg->buf[y * cimg->height / height * cimg->width * 4]; for(x = 0; x < width; x++) { - *newbuf++ = (ibuf[(bufx >> 10)*4+2]); - *newbuf++ = (ibuf[(bufx >> 10)*4+1]); - *newbuf++ = (ibuf[(bufx >> 10)*4+0]); + a = (ibuf[(bufx >> 10)*4+3]) / 255.0f; + *newbuf++ = (ibuf[(bufx >> 10)*4+2] * a) + (bg.blue * (1 - a)); + *newbuf++ = (ibuf[(bufx >> 10)*4+1] * a) + (bg.green * (1 - a)); + *newbuf++ = (ibuf[(bufx >> 10)*4+0] * a) + (bg.red * (1 - a)); newbuf++; bufx += dx; } @@ -308,7 +313,7 @@ draw(void) xoffset -= cimg->view.panxoffset; yoffset -= cimg->view.panyoffset; } - XSetForeground(dpy, gc, BlackPixel(dpy, 0)); + XSetForeground(dpy, gc, bg.pixel); XFillRectangle(dpy, xpix, gc, 0, 0, winwidth, winheight); XPutImage(dpy, xpix, gc, ximg, 0, 0, xoffset, yoffset, ximg->width, ximg->height); XCopyArea(dpy, xpix, win, gc, 0, 0, winwidth, winheight, 0, 0); @@ -513,7 +518,9 @@ setup(void) DefaultDepth(dpy, screen), InputOutput, CopyFromParent, 0, NULL); gc = XCreateGC(dpy, win, 0, NULL); - + cmap = DefaultColormap(dpy, screen); + if(!XAllocNamedColor(dpy, cmap, bgcolor, &bg, &bg)) + die("cannot allocate color\n"); XStoreName(dpy, win, wintitle); XSelectInput(dpy, win, StructureNotifyMask | ExposureMask | KeyPressMask | ButtonPressMask);