diff options
Diffstat (limited to 'plugins/omemo/vapi')
| -rw-r--r-- | plugins/omemo/vapi/libqrencode.vapi | 51 |
1 files changed, 35 insertions, 16 deletions
diff --git a/plugins/omemo/vapi/libqrencode.vapi b/plugins/omemo/vapi/libqrencode.vapi index 253e239a..79f98b62 100644 --- a/plugins/omemo/vapi/libqrencode.vapi +++ b/plugins/omemo/vapi/libqrencode.vapi @@ -38,26 +38,45 @@ namespace Qrencode { public Pixbuf to_pixbuf(int module_size) { GLib.assert(module_size > 0); - var src_w = width; - var src = data[0:width*width]; - var dst_w = src_w*module_size; - var dst = new uint8[dst_w*dst_w*3]; - for (int src_y = 0; src_y < src_w; src_y++) { - for (int repeat_y = 0; repeat_y < module_size; repeat_y++) { - var dst_y = src_y*module_size + repeat_y; - for (int src_x = 0; src_x < src_w; src_x++) { - uint8 color = (src[src_y*src_w + src_x] & 1) == 1 ? 0 : 255; - for (int repeat_x = 0; repeat_x < module_size; repeat_x++) { - var dst_x = src_x*module_size + repeat_x; - var px_idx = dst_y*dst_w + dst_x; - dst[px_idx*3+0] = color; - dst[px_idx*3+1] = color; - dst[px_idx*3+2] = color; + var dst_width = width*module_size; + var dst_data = new uint8[dst_width*dst_width*3]; + expand_and_upsample(data,width,width, dst_data,dst_width,dst_width); + return new Pixbuf.from_data(dst_data, + Colorspace.RGB, false, 8, dst_width, dst_width, dst_width*3); + } + + /** Does 2D nearest-neighbor upsampling of an array of single-byte + * samples, while expanding the least significant bit of each sample + * to three 0-or-255 bytes. + */ + private void expand_and_upsample( + uint8[] src, uint src_w, uint src_h, + uint8[] dst, uint dst_w, uint dst_h) { + GLib.assert(dst_w % src_w == 0); + GLib.assert(dst_h % src_h == 0); + var scale_x = dst_w/src_w, + scale_y = dst_h/src_h; + /* Doing the iteration in the order of destination samples for + * improved cache-friendliness (dst is 48 times larger than src in + * the typical case of scaling by 4x4). + * The choice of multiple nested loops over a single one is for + * avoiding a ton of divisions by non-constants. + */ + for (uint src_y = 0; src_y < src_h; ++src_y) { + for (uint repeat_y = 0; repeat_y < scale_y; ++repeat_y) { + var dst_y = src_y*scale_y + repeat_y; + for (uint src_x = 0; src_x < src_w; ++src_x) { + uint8 value = (src[src_y*src_w + src_x] & 1)==1 ? 0:255; + for (uint repeat_x = 0; repeat_x < scale_x; ++repeat_x){ + var dst_x = src_x*scale_x + repeat_x; + var dst_idx = dst_y*dst_w + dst_x; + dst[dst_idx*3+0] = value; + dst[dst_idx*3+1] = value; + dst[dst_idx*3+2] = value; } } } } - return new Pixbuf.from_data(dst, Colorspace.RGB, false, 8, dst_w, dst_w, dst_w*3); } } } |