Difference between revisions of "GIMP/C2/Selecting-Sections-Part-1/English-timed"

|Welcome to the tutorial of Meet The GIMP. My name is Rolf steinort and I am recording this is Bremen, Northen Germany.  

| Lets start todays tutorial with this image. Today I'll work with this image only to use it as an example.  

|This square is a selection and this part is outside of the selection. These moving lines here are the border of the selection.  

|The GIMP people call a selection as a channel. A channel like red, green or blue or an alpha channel which controls the transperancy. Outside of the selection, the value of this channel is zero. And inside its 255 ,and between them is the border, and between them there can be values lower than 255 and higher than zero. So changing a selection or making a selection is changing some numbers.  

|For de-selecting a selection there are 2 ways. 1st way is, go to Select and None. You can also use the key combination of Shift + Ctr l+ A and get rid of a selection. Now select, the Rectangle Select Tool. And look into the options dialog.  

|On top there are four choices. The 1st one is replace the current selection. So I select different areas here, and you can see that when I select a new area, the old selection is deleted.  

| The 2nd option is add to the current selection. By selecting that option, I can select different areas in the image and get a quite complicated selection.  

|Its a bit complicated. Press Ctrl + Z to undo the filling. And shift + Ctrl + A to de-select everything. And back to my options dialog.  

|Now select a square here and select Subtract from the Current Selection. I Select this area but nothing happens. But when I select these area you can see that the edge is cut out. You can see that the frame of selection stays there and when I move it , changes can be made.  

|Now the last option is Intersect with the current selection. Lets try that.  

|I select a rectangle here and the area outside it is not selected and selections which were done before are deleted. And only selection in this rectangle is kept. I can also modify this rectangle until I have the area selected that I wanted.

|You can replace a selection by just clicking. Adding can be done by Click and Shift. So lets try that, I press the shift key and then by clicking I start adding new selections. And when I press the shift key and mouse key, a plus sign appears.  

|Now if I want to subtract the selection, I can press the ctrl key and now I press the mouse key and start to move you can see a minus sign. So now I can substract the selection.  

|If you memorize these key combinations you can select the area faster. And the same key are used by the other selection tool. So you'll just have to learn them only once.   

|Next option is Feather Edges, and when it you get another option here as Radius Count. So I increase it a bit and select an area. Now you can see here, there is rounded corner. I don’t want rounded corners here. Just to show you what has happened i'll fill this with black and I zoom into the image.  

|So the half black colour fade's inside the selection and half outside. The margin ends is the only  real border of your selection when you have a hard selection.

|Feather edges is a nice option to get smooth selections. With  feather selection you can get a less sharp seen and it is easier that way.  

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|The next option is Rounded Corners. It’s a rectangle with rounded corner and you can set the radius of the rounded corners. Here is the round part and these margins are the straight parts.

|Here is the next option Antialiasing. This option sets the corner painting. I just fill this selection with black and now I go back to my selection tool and i de-select antialiasing and make another selection and fill this also with black.  

|So select the zoom tool and deselect all selections with Shift + Ctrl + A and zoom into this area. And here the edge is without antialiasing and it is either filled with black or not filled with black. And here you can see the stair of grays.  

|Here you can see the smooth corner without jaggis, and that’s called Antialiasing. This selection does not have a rounded corner but it's series of steps.  

| So if you want to have smooth corners then select Antialiasing. And if you want to have these gray tones in here then de-select that option.  

|So I select that option and there is a sub option called Expand From Centre I select it and start working with it.  

|So I place a point here and I start pulling my selection from here. You can see it grow from that point and this point is always in the middle of the selection. When I deselect that option I can pull selection here and the position of the corner changes according to my selection.  

|There is a key code for this. When I click at this point and press ctrl  I have a selection from centre and the selection expands from centre. And when I release the ctrl key, the selection vanishes.  

| When I press the Ctrl key before I press the mouse button, I can substract a selection  but when I first press the mouse key and then the Ctrl key I get selection from centre. The next option here is Fixed Aspect Ratio and I can have here pre-selected aspect ratio as 1 by 1 and when I draw it will always be a square.   

|There is another way to create a perfect square. I start the selection at this point and pull and then press shift.Now the fixed aspect ratio is selected with pre-selected value here.  

|The next option is highlight and when I use that, the area that is not selected is gray and all the area that is selected is white. And this concerns only the current selection so lets de-select it and look at other options. Here you can set these values by hand and if you click on fix here, then I can't change the size of the selection.But if I want to have set width two pixels less and height one pixel more so it fine tunes the selection.  

| I can move the selection a little bit to the right by increasing the value of X which is the point of origin. An when I click on fix, I can move the whole selection. So the ‘X’ and ‘Y’ value is the point of origin of the left top point and with fix button I can block the movement.  

| The next option is the guides. I can select a Centre Line which shows me where the middle point of the selection is. I can have the Rule Of Thirds, which is used for the graphic work or I can have the Golden Selections which is similar to the Rule Of Thirds.  

| On the bottom is Auto Shrink Selection and Shrink Merged. Auto Shrink Selection is not very useful. But Shrink Merged is an option which if selected, the algorithm looks at the all the layers, and if de-selected only the layer that you are working on is taken into consideration.  

|Before having a recap of these options we'll talk about Ellipse Selection. So de-select all the selections by pressing Shift+ctrl+A. On the top you get the same options like Replace current selection, Add to the selection with Shift key before clicking and Subtract with Ctrl key before clicking and Intersect with Shift and Ctrl key before clicking.  

| Antialiasing is again for smooth edges. It is more important with ellipse then with rectangles because ellipse are always round.  

|Feather edges the same option as in rectangle. When I fill it with black , you can see a smooth gradient between black and white and these margin ends are in between black and white.  

|Fixed aspect ratio is also the same, after clicking the mouse button you get a perfect circle with aspect ratio 1 by 1. Now lets come to the last tool I want to show you for today and thats the Free Select tool.  

| When I select that tool I see the same options here and also the keys work the same for Add, Replace, Subtract and Intersect. It has only 2 further option i.e Antialiasing and feather edges with same functions. Here I get the radius of the circle and i de-select it now.  

| I select this lower part of the leaf to show you as example. And I click into the image where I want to start the selection and draw a line and follow the border of the leaf.

|So now I have selected this area. I zoom into the image to do fine tuning. And in my selection dialog I select Add To The Current Selection and start adjusting the selection.  

|The algorithm looks for the shortest way to the point where you started the selection. For making the selection easy I can use a Quick Mask.  

| It is a bit confusing option because the area which I have selected and the area which is not selected is shown in red. So I go to the toggle and right clicking on it gives me Configure, Colour and Opacity and here I can set a color so i set it to blue.  

| Now the area which is selected is Red and all the area is blue. And now I select a pen and start painting the selected area but before that I change the foreground and background colour  with the key ’X’. And now I start to paint.  

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|And when I untoggle the mask, you can see here is the mistake in selection and here also. So I select the toggle and correct the mistakes.

|So the Quick Mask is an easy way to get a complicated selection right. You can use the quick selection as a tool.  

|You can change the opacity of the mask and now you can hardly see the parts which is not selected. 50% opacity is the right amount in most of the cases.

|There is another option here called mask selected areas. It has just the opposite effect of the quick mask. So now the selected area is painted blue and this looks better in this case here. And when you de-select the quick mask, you can see your selection.  

|I save it as Mask 1 and it will be stored with the ’XCF’ file. So now I can de-select everything with Shift + Ctrl + A. Select another part, and when I go back to my selection here I can add to the selection or subtract from selection or even intersect with selection and my selection is back here.