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Add gravity support to crop #45

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Lovell Fuller
2014-08-21 11:01:25 +01:00
parent 8ef0851a49
commit 5fe945fca8
5 changed files with 115 additions and 9 deletions
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44
src/sharp.cc
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@@ -3,6 +3,7 @@
#include <math.h>
#include <string>
#include <string.h>
#include <tuple>
#include <vips/vips.h>
#include "nan.h"
@@ -20,6 +21,7 @@ struct resize_baton {
int width;
int height;
bool crop;
int gravity;
bool max;
VipsExtend extend;
bool sharpen;
@@ -36,6 +38,7 @@ struct resize_baton {
buffer_in_len(0),
buffer_out_len(0),
crop(false),
gravity(0),
max(false),
sharpen(false),
progressive(false),
@@ -94,7 +97,8 @@ static void resize_error(resize_baton *baton, VipsImage *unref) {
2. Use input image EXIF Orientation header (does not support mirroring)
3. Otherwise default to zero, i.e. no rotation
*/
static VipsAngle calc_rotation(int const angle, VipsImage const *input) {
static VipsAngle
sharp_calc_rotation(int const angle, VipsImage const *input) {
VipsAngle rotate = VIPS_ANGLE_0;
if (angle == -1) {
const char *exif;
@@ -119,6 +123,36 @@ static VipsAngle calc_rotation(int const angle, VipsImage const *input) {
return rotate;
}
/*
Calculate the (left, top) coordinates of the output image
within the input image, applying the given gravity.
*/
static std::tuple<int, int>
sharp_calc_crop(int const inWidth, int const inHeight, int const outWidth, int const outHeight, int const gravity) {
int left = 0;
int top = 0;
switch (gravity) {
case 1: // North
left = (inWidth - outWidth + 1) / 2;
break;
case 2: // East
left = inWidth - outWidth;
top = (inHeight - outHeight + 1) / 2;
break;
case 3: // South
left = (inWidth - outWidth + 1) / 2;
top = inHeight - outHeight;
break;
case 4: // West
top = (inHeight - outHeight + 1) / 2;
break;
default: // Centre
left = (inWidth - outWidth + 1) / 2;
top = (inHeight - outHeight + 1) / 2;
}
return std::make_tuple(left, top);
}
class ResizeWorker : public NanAsyncWorker {
public:
ResizeWorker(NanCallback *callback, resize_baton *baton)
@@ -189,7 +223,7 @@ class ResizeWorker : public NanAsyncWorker {
int inputHeight = in->Ysize;
// Calculate angle of rotation, to be carried out later
VipsAngle rotation = calc_rotation(baton->angle, in);
VipsAngle rotation = sharp_calc_rotation(baton->angle, in);
if (rotation == VIPS_ANGLE_90 || rotation == VIPS_ANGLE_270) {
// Swap input output width and height when rotating by 90 or 270 degrees
int swap = inputWidth;
@@ -337,10 +371,11 @@ class ResizeWorker : public NanAsyncWorker {
if (rotated->Xsize != baton->width || rotated->Ysize != baton->height) {
if (baton->crop || baton->max) {
// Crop/max
int left;
int top;
std::tie(left, top) = sharp_calc_crop(rotated->Xsize, rotated->Ysize, baton->width, baton->height, baton->gravity);
int width = std::min(rotated->Xsize, baton->width);
int height = std::min(rotated->Ysize, baton->height);
int left = (rotated->Xsize - width + 1) / 2;
int top = (rotated->Ysize - height + 1) / 2;
if (vips_extract_area(rotated, &canvased, left, top, width, height, NULL)) {
return resize_error(baton, rotated);
}
@@ -507,6 +542,7 @@ NAN_METHOD(resize) {
baton->max = true;
}
// Other options
baton->gravity = options->Get(NanNew<String>("gravity"))->Int32Value();
baton->sharpen = options->Get(NanNew<String>("sharpen"))->BooleanValue();
baton->interpolator = *String::Utf8Value(options->Get(NanNew<String>("interpolator"))->ToString());
baton->progressive = options->Get(NanNew<String>("progressive"))->BooleanValue();