// Copyright 2019 The MediaPipe Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "mediapipe/calculators/image/scale_image_utils.h"
#include <math.h>
#include <string>
#include "absl/log/absl_check.h"
#include "absl/strings/str_split.h"
#include "mediapipe/framework/port/logging.h"
#include "mediapipe/framework/port/ret_check.h"
#include "mediapipe/framework/port/status.h"
namespace mediapipe {
namespace scale_image {
namespace {
double ParseRational(const std::string& rational) {
const std::vector<std::string> v = absl::StrSplit(rational, '/');
const double numerator = std::strtod(v[0].c_str(), nullptr);
const double denominator = std::strtod(v[1].c_str(), nullptr);
return numerator / denominator;
}
} // namespace
absl::Status FindCropDimensions(int input_width, int input_height, //
const std::string& min_aspect_ratio, //
const std::string& max_aspect_ratio, //
int* crop_width, int* crop_height, //
int* col_start, int* row_start) {
ABSL_CHECK(crop_width);
ABSL_CHECK(crop_height);
ABSL_CHECK(col_start);
ABSL_CHECK(row_start);
double min_aspect_ratio_q = 0.0;
double max_aspect_ratio_q = 0.0;
if (!min_aspect_ratio.empty()) {
min_aspect_ratio_q = ParseRational(min_aspect_ratio);
}
if (!max_aspect_ratio.empty()) {
max_aspect_ratio_q = ParseRational(max_aspect_ratio);
}
*crop_width = input_width;
*crop_height = input_height;
*col_start = 0;
*row_start = 0;
// Determine the current aspect ratio.
const double aspect_ratio =
static_cast<double>(input_width) / static_cast<double>(input_height);
if (!std::isinf(max_aspect_ratio_q) && !std::isinf(min_aspect_ratio_q)) {
if (max_aspect_ratio_q > 0 && aspect_ratio > max_aspect_ratio_q) {
// Determine the width based on the height multiplied by the max
// aspect ratio.
*crop_width = static_cast<int>(static_cast<double>(input_height) *
max_aspect_ratio_q);
*crop_width = (*crop_width / 2) * 2;
// The col_start should be half the difference between the input width
// and the output width.
*col_start = (input_width - *crop_width) / 2;
} else if (min_aspect_ratio_q > 0 && aspect_ratio < min_aspect_ratio_q) {
// Determine the height based on the width divided by the min
// aspect ratio.
*crop_height = static_cast<int>(static_cast<double>(input_width) /
min_aspect_ratio_q);
*crop_height = (*crop_height / 2) * 2;
*row_start = (input_height - *crop_height) / 2;
}
}
ABSL_CHECK_LE(*crop_width, input_width);
ABSL_CHECK_LE(*crop_height, input_height);
return absl::OkStatus();
}
absl::Status FindOutputDimensions(int input_width, //
int input_height, //
int target_width, //
int target_height, //
int target_max_area, //
bool preserve_aspect_ratio, //
int scale_to_multiple_of, //
int* output_width, int* output_height) {
ABSL_CHECK(output_width);
ABSL_CHECK(output_height);
if (target_max_area > 0 && input_width * input_height > target_max_area) {
preserve_aspect_ratio = true;
target_height = static_cast<int>(sqrt(static_cast<double>(target_max_area) /
(static_cast<double>(input_width) /
static_cast<double>(input_height))));
target_width = -1; // Resize width to preserve aspect ratio.
}
if (preserve_aspect_ratio) {
RET_CHECK(scale_to_multiple_of == 2)
<< "FindOutputDimensions always outputs width and height that are "
"divisible by 2 when preserving aspect ratio. If you'd like to "
"set scale_to_multiple_of to something other than 2, please "
"set preserve_aspect_ratio to false.";
}
if (scale_to_multiple_of < 1) scale_to_multiple_of = 1;
if (!preserve_aspect_ratio || (target_width <= 0 && target_height <= 0)) {
if (target_width <= 0) {
target_width = input_width;
}
if (target_height <= 0) {
target_height = input_height;
}
target_width -= target_width % scale_to_multiple_of;
target_height -= target_height % scale_to_multiple_of;
*output_width = target_width;
*output_height = target_height;
return absl::OkStatus();
}
if (target_width > 0) {
// Try setting the height based on the width and the aspect ratio.
int try_width = target_width;
int try_height = static_cast<int>(static_cast<double>(target_width) /
static_cast<double>(input_width) *
static_cast<double>(input_height));
try_width = (try_width / 2) * 2;
try_height = (try_height / 2) * 2;
// The output width/height should be greater than 0.
try_width = std::max(try_width, 1);
try_height = std::max(try_height, 1);
if (target_height <= 0 || try_height <= target_height) {
// The resulting height based on the target width and aspect ratio
// was within the image, so use these dimensions.
*output_width = try_width;
*output_height = try_height;
return absl::OkStatus();
}
}
if (target_height > 0) {
// Try setting the width based on the height and the aspect ratio.
int try_height = target_height;
int try_width = static_cast<int>(static_cast<double>(target_height) /
static_cast<double>(input_height) *
static_cast<double>(input_width));
try_width = (try_width / 2) * 2;
try_height = (try_height / 2) * 2;
// The output width/height should be greater than 0.
try_width = std::max(try_width, 1);
try_height = std::max(try_height, 1);
if (target_width <= 0 || try_width <= target_width) {
// The resulting width based on the target width and aspect ratio
// was within the image, so use these dimensions.
*output_width = try_width;
*output_height = try_height;
return absl::OkStatus();
}
}
RET_CHECK_FAIL()
<< "Unable to set output dimensions based on target dimensions.";
}
absl::Status FindOutputDimensions(int input_width, //
int input_height, //
int target_width, //
int target_height, //
bool preserve_aspect_ratio, //
int scale_to_multiple_of, //
int* output_width, int* output_height) {
return FindOutputDimensions(
input_width, input_height, target_width, target_height, -1,
preserve_aspect_ratio, scale_to_multiple_of, output_width, output_height);
}
} // namespace scale_image
} // namespace mediapipe
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