309 lines
12 KiB
C
309 lines
12 KiB
C
/* bitmap_scale.c - Bitmap scaling. */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2006,2007,2008,2009 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/mm.h>
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#include <grub/misc.h>
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#include <grub/video.h>
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#include <grub/bitmap.h>
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#include <grub/bitmap_scale.h>
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#include <grub/types.h>
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/* Prototypes for module-local functions. */
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static grub_err_t scale_nn (struct grub_video_bitmap *dst,
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struct grub_video_bitmap *src);
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static grub_err_t scale_bilinear (struct grub_video_bitmap *dst,
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struct grub_video_bitmap *src);
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/* This function creates a new scaled version of the bitmap SRC. The new
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bitmap has dimensions DST_WIDTH by DST_HEIGHT. The scaling algorithm
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is given by SCALE_METHOD. If an error is encountered, the return code is
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not equal to GRUB_ERR_NONE, and the bitmap DST is either not created, or
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it is destroyed before this function returns.
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Supports only direct color modes which have components separated
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into bytes (e.g., RGBA 8:8:8:8 or BGR 8:8:8 true color).
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But because of this simplifying assumption, the implementation is
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greatly simplified. */
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grub_err_t
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grub_video_bitmap_create_scaled (struct grub_video_bitmap **dst,
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int dst_width, int dst_height,
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struct grub_video_bitmap *src,
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enum grub_video_bitmap_scale_method
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scale_method)
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{
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*dst = 0;
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/* Verify the simplifying assumptions. */
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if (src == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT,
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"null src bitmap in grub_video_bitmap_create_scaled");
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if (src->mode_info.red_field_pos % 8 != 0
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|| src->mode_info.green_field_pos % 8 != 0
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|| src->mode_info.blue_field_pos % 8 != 0
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|| src->mode_info.reserved_field_pos % 8 != 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT,
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"src format not supported for scale");
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if (src->mode_info.width == 0 || src->mode_info.height == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT,
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"source bitmap has a zero dimension");
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if (dst_width <= 0 || dst_height <= 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT,
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"requested to scale to a size w/ a zero dimension");
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if (src->mode_info.bytes_per_pixel * 8 != src->mode_info.bpp)
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return grub_error (GRUB_ERR_BAD_ARGUMENT,
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"bitmap to scale has inconsistent Bpp and bpp");
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/* Create the new bitmap. */
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grub_err_t ret;
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ret = grub_video_bitmap_create (dst, dst_width, dst_height,
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src->mode_info.blit_format);
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if (ret != GRUB_ERR_NONE)
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return ret; /* Error. */
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switch (scale_method)
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{
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case GRUB_VIDEO_BITMAP_SCALE_METHOD_FASTEST:
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case GRUB_VIDEO_BITMAP_SCALE_METHOD_NEAREST:
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ret = scale_nn (*dst, src);
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break;
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case GRUB_VIDEO_BITMAP_SCALE_METHOD_BEST:
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case GRUB_VIDEO_BITMAP_SCALE_METHOD_BILINEAR:
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ret = scale_bilinear (*dst, src);
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break;
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default:
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ret = grub_error (GRUB_ERR_BAD_ARGUMENT, "Invalid scale_method value");
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break;
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}
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if (ret == GRUB_ERR_NONE)
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{
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/* Success: *dst is now a pointer to the scaled bitmap. */
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return GRUB_ERR_NONE;
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}
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else
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{
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/* Destroy the bitmap and return the error code. */
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grub_video_bitmap_destroy (*dst);
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*dst = 0;
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return ret;
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}
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}
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/* Nearest neighbor bitmap scaling algorithm.
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Copy the bitmap SRC to the bitmap DST, scaling the bitmap to fit the
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dimensions of DST. This function uses the nearest neighbor algorithm to
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interpolate the pixels.
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Supports only direct color modes which have components separated
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into bytes (e.g., RGBA 8:8:8:8 or BGR 8:8:8 true color).
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But because of this simplifying assumption, the implementation is
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greatly simplified. */
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static grub_err_t
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scale_nn (struct grub_video_bitmap *dst, struct grub_video_bitmap *src)
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{
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/* Verify the simplifying assumptions. */
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if (dst == 0 || src == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "null bitmap in scale_nn");
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if (dst->mode_info.red_field_pos % 8 != 0
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|| dst->mode_info.green_field_pos % 8 != 0
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|| dst->mode_info.blue_field_pos % 8 != 0
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|| dst->mode_info.reserved_field_pos % 8 != 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "dst format not supported");
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if (src->mode_info.red_field_pos % 8 != 0
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|| src->mode_info.green_field_pos % 8 != 0
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|| src->mode_info.blue_field_pos % 8 != 0
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|| src->mode_info.reserved_field_pos % 8 != 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "src format not supported");
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if (dst->mode_info.red_field_pos != src->mode_info.red_field_pos
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|| dst->mode_info.red_mask_size != src->mode_info.red_mask_size
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|| dst->mode_info.green_field_pos != src->mode_info.green_field_pos
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|| dst->mode_info.green_mask_size != src->mode_info.green_mask_size
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|| dst->mode_info.blue_field_pos != src->mode_info.blue_field_pos
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|| dst->mode_info.blue_mask_size != src->mode_info.blue_mask_size
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|| dst->mode_info.reserved_field_pos !=
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src->mode_info.reserved_field_pos
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|| dst->mode_info.reserved_mask_size !=
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src->mode_info.reserved_mask_size)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "dst and src not compatible");
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if (dst->mode_info.bytes_per_pixel != src->mode_info.bytes_per_pixel)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "dst and src not compatible");
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if (dst->mode_info.width == 0 || dst->mode_info.height == 0
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|| src->mode_info.width == 0 || src->mode_info.height == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "bitmap has a zero dimension");
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grub_uint8_t *ddata = dst->data;
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grub_uint8_t *sdata = src->data;
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int dw = dst->mode_info.width;
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int dh = dst->mode_info.height;
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int sw = src->mode_info.width;
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int sh = src->mode_info.height;
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int dstride = dst->mode_info.pitch;
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int sstride = src->mode_info.pitch;
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/* bytes_per_pixel is the same for both src and dst. */
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int bytes_per_pixel = dst->mode_info.bytes_per_pixel;
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int dy;
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for (dy = 0; dy < dh; dy++)
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{
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int dx;
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for (dx = 0; dx < dw; dx++)
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{
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grub_uint8_t *dptr;
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grub_uint8_t *sptr;
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int sx;
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int sy;
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int comp;
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/* Compute the source coordinate that the destination coordinate
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maps to. Note: sx/sw = dx/dw => sx = sw*dx/dw. */
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sx = sw * dx / dw;
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sy = sh * dy / dh;
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/* Get the address of the pixels in src and dst. */
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dptr = ddata + dy * dstride + dx * bytes_per_pixel;
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sptr = sdata + sy * sstride + sx * bytes_per_pixel;
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/* Copy the pixel color value. */
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for (comp = 0; comp < bytes_per_pixel; comp++)
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dptr[comp] = sptr[comp];
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}
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}
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return GRUB_ERR_NONE;
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}
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/* Bilinear interpolation image scaling algorithm.
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Copy the bitmap SRC to the bitmap DST, scaling the bitmap to fit the
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dimensions of DST. This function uses the bilinear interpolation algorithm
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to interpolate the pixels.
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Supports only direct color modes which have components separated
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into bytes (e.g., RGBA 8:8:8:8 or BGR 8:8:8 true color).
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But because of this simplifying assumption, the implementation is
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greatly simplified. */
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static grub_err_t
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scale_bilinear (struct grub_video_bitmap *dst, struct grub_video_bitmap *src)
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{
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/* Verify the simplifying assumptions. */
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if (dst == 0 || src == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "null bitmap in scale func");
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if (dst->mode_info.red_field_pos % 8 != 0
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|| dst->mode_info.green_field_pos % 8 != 0
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|| dst->mode_info.blue_field_pos % 8 != 0
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|| dst->mode_info.reserved_field_pos % 8 != 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "dst format not supported");
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if (src->mode_info.red_field_pos % 8 != 0
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|| src->mode_info.green_field_pos % 8 != 0
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|| src->mode_info.blue_field_pos % 8 != 0
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|| src->mode_info.reserved_field_pos % 8 != 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "src format not supported");
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if (dst->mode_info.red_field_pos != src->mode_info.red_field_pos
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|| dst->mode_info.red_mask_size != src->mode_info.red_mask_size
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|| dst->mode_info.green_field_pos != src->mode_info.green_field_pos
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|| dst->mode_info.green_mask_size != src->mode_info.green_mask_size
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|| dst->mode_info.blue_field_pos != src->mode_info.blue_field_pos
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|| dst->mode_info.blue_mask_size != src->mode_info.blue_mask_size
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|| dst->mode_info.reserved_field_pos !=
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src->mode_info.reserved_field_pos
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|| dst->mode_info.reserved_mask_size !=
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src->mode_info.reserved_mask_size)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "dst and src not compatible");
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if (dst->mode_info.bytes_per_pixel != src->mode_info.bytes_per_pixel)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "dst and src not compatible");
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if (dst->mode_info.width == 0 || dst->mode_info.height == 0
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|| src->mode_info.width == 0 || src->mode_info.height == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "bitmap has a zero dimension");
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grub_uint8_t *ddata = dst->data;
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grub_uint8_t *sdata = src->data;
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int dw = dst->mode_info.width;
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int dh = dst->mode_info.height;
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int sw = src->mode_info.width;
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int sh = src->mode_info.height;
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int dstride = dst->mode_info.pitch;
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int sstride = src->mode_info.pitch;
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/* bytes_per_pixel is the same for both src and dst. */
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int bytes_per_pixel = dst->mode_info.bytes_per_pixel;
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int dy;
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for (dy = 0; dy < dh; dy++)
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{
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int dx;
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for (dx = 0; dx < dw; dx++)
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{
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grub_uint8_t *dptr;
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grub_uint8_t *sptr;
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int sx;
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int sy;
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int comp;
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/* Compute the source coordinate that the destination coordinate
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maps to. Note: sx/sw = dx/dw => sx = sw*dx/dw. */
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sx = sw * dx / dw;
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sy = sh * dy / dh;
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/* Get the address of the pixels in src and dst. */
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dptr = ddata + dy * dstride + dx * bytes_per_pixel;
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sptr = sdata + sy * sstride + sx * bytes_per_pixel;
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/* If we have enough space to do so, use bilinear interpolation.
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Otherwise, fall back to nearest neighbor for this pixel. */
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if (sx < sw - 1 && sy < sh - 1)
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{
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/* Do bilinear interpolation. */
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/* Fixed-point .8 numbers representing the fraction of the
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distance in the x (u) and y (v) direction within the
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box of 4 pixels in the source. */
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int u = (256 * sw * dx / dw) - (sx * 256);
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int v = (256 * sh * dy / dh) - (sy * 256);
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for (comp = 0; comp < bytes_per_pixel; comp++)
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{
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/* Get the component's values for the
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four source corner pixels. */
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grub_uint8_t f00 = sptr[comp];
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grub_uint8_t f10 = sptr[comp + bytes_per_pixel];
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grub_uint8_t f01 = sptr[comp + sstride];
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grub_uint8_t f11 = sptr[comp + sstride + bytes_per_pixel];
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/* Do linear interpolations along the top and bottom
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rows of the box. */
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grub_uint8_t f0y = (256 - v) * f00 / 256 + v * f01 / 256;
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grub_uint8_t f1y = (256 - v) * f10 / 256 + v * f11 / 256;
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/* Interpolate vertically. */
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grub_uint8_t fxy = (256 - u) * f0y / 256 + u * f1y / 256;
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dptr[comp] = fxy;
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}
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}
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else
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{
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/* Fall back to nearest neighbor interpolation. */
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/* Copy the pixel color value. */
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for (comp = 0; comp < bytes_per_pixel; comp++)
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dptr[comp] = sptr[comp];
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}
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}
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}
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return GRUB_ERR_NONE;
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}
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